SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549


SCHEDULE 13D

Under the Securities Exchange Act of 1934



UniSource Energy Corporation
(Name of Issuer)

Common Stock, No Par Value Per Share
(Title of Class of Securities)



________909205106________
(CUSIP Number)

James E. McKee
Gabelli Asset Management Inc.
One Corporate Center
Rye, New York 10580-1435
(914) 921-5294
(Name, Address and Telephone Number of Person
Authorized to Receive Notices and Communications)


_________December 17, 2003_________
(Date of Event which Requires Filing of this Statement)


If the filing person has previously filed a statement on Schedule
13G to report the acquisition that is the subject of this Schedule
13D, and is filing this schedule because of Sections 240.13d-1(e),
240.13d-1(f) or 240.13d-1(g), check the following box  0.



CUSIP No. 909205106
1
NAMES OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

Gabelli Funds, LLC I.D. NO.  13-4044523
2
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
(a)
(b)

3
SEC USE ONLY

4
SOURCE OF FUNDS (SEE INSTRUCTIONS)
    00-Funds of investment advisory clients

5
CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
PURSUANT TO ITEMS 2 (d) OR 2 (e)


6
CITIZENSHIP OR PLACE OF ORGANIZATION
   New York

NUMBER OF

SHARES

BENEFICIALLY

OWNED

BY EACH

REPORTING

PERSON

WITH
:
7
:
:
:
SOLE VOTING POWER

1,015,200 (Item 5)

:
8
:
:
:
SHARED VOTING POWER

NONE

:
9
:
:
:
SOLE DISPOSITIVE POWER

1,015,200 (Item 5)

:10
:
:
:
SHARED DISPOSITIVE POWER

NONE
11



AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

1,015,200 (Item 5)
12



CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES
(SEE INSTRUCTIONS)
13



PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

3.01%
14



TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
    IA
CUSIP No. 909205106
1
NAMES OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

GAMCO Investors, Inc.
I.D. NO.  13-4044521
2
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
(a)
(b)

3
SEC USE ONLY

4
SOURCE OF FUNDS (SEE INSTRUCTIONS)
 00-Funds of investment advisory clients

5
CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
PURSUANT TO ITEMS 2 (d) OR 2 (e)


6
CITIZENSHIP OR PLACE OF ORGANIZATION
   New York

NUMBER OF

SHARES

BENEFICIALLY

OWNED

BY EACH

REPORTING

PERSON

WITH
:
7
:
:
:
SOLE VOTING POWER

752,700 (Item 5)

:
8
:
:
:
SHARED VOTING POWER

NONE

:
9
:
:
:
SOLE DISPOSITIVE POWER

814,700 (Item 5)

:10
:
:
:
SHARED DISPOSITIVE POWER

NONE
11



AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

814,700 (Item 5)
12



CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES
(SEE INSTRUCTIONS)
13



PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

2.42%
14



TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
    IA, CO

CUSIP No. 909205106

1
NAMES OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

MJG Associates, Inc.
I.D. NO.  06-1304269
2
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
(a)
(b)

3
SEC USE ONLY


4
SOURCE OF FUNDS (SEE INSTRUCTIONS)
00-Client Funds

5
CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
PURSUANT TO ITEMS 2 (d) OR 2 (e)


6
CITIZENSHIP OR PLACE OF ORGANIZATION
   Connecticut

NUMBER OF

SHARES

BENEFICIALLY

OWNED

BY EACH

REPORTING

PERSON

WITH
:
7
:
:
:
SOLE VOTING POWER

2,000 (Item 5)

:
8
:
:
:
SHARED VOTING POWER

NONE

:
9
:
:
:
SOLE DISPOSITIVE POWER

2,000 (Item 5)

:10
:
:
:
SHARED DISPOSITIVE POWER

NONE
11



AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

2,000 (ITEM 5)
12



CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES
 (SEE INSTRUCTIONS)
13



PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

0.01%
6
CITIZENSHIP OR PLACE OF ORGANIZATION
   Delaware

CUSIP No. 909205106
1
NAMES OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

Gabelli Securities, Inc.   I.D. NO.  13-3379374
2
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
(a)
(b)

3
SEC USE ONLY

4
SOURCE OF FUNDS (SEE INSTRUCTIONS)
00-Client Funds

5
CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
PURSUANT TO ITEMS 2 (d) OR 2 (e)


6
CITIZENSHIP OR PLACE OF ORGANIZATION
   Delaware

NUMBER OF

SHARES

BENEFICIALLY

OWNED

BY EACH

REPORTING

PERSON

WITH
:
7
:
:
:
SOLE VOTING POWER

  249,600    (Item 5)

:
8
:
:
:
SHARED VOTING POWER

NONE

:
9
:
:
:
SOLE DISPOSITIVE POWER

   249,600     (Item 5)

:10
:
:
:
SHARED DISPOSITIVE POWER

NONE
11



AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

249,600               (ITEM 5)
12



CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES
(SEE INSTRUCTIONS)
13



PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
0.74%
14



TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
    HC, CO

CUSIP No. 909205106
1
NAMES OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

Gabelli Foundation, Inc.
I.D. NO.  94-2975159
2
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
(a)
(b)

3
SEC USE ONLY

4
SOURCE OF FUNDS (SEE INSTRUCTIONS)
 WC

5
CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
PURSUANT TO ITEMS 2 (d) OR 2 (e)


6
CITIZENSHIP OR PLACE OF ORGANIZATION
   NV

NUMBER OF

SHARES

BENEFICIALLY

OWNED

BY EACH

REPORTING

PERSON

WITH
:
7
:
:
:
SOLE VOTING POWER

 10,000     (Item 5)

:
8
:
:
:
SHARED VOTING POWER

NONE

:
9
:
:
:
SOLE DISPOSITIVE POWER

   10,000     (Item 5)

:10
:
:
:
SHARED DISPOSITIVE POWER

NONE
11



AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

10,000               (ITEM 5)
12



CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES
(SEE INSTRUCTIONS)
13



PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
0.03%
14



TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
    00-PRIVATE FOUNDATION

CUSIP No. 909205106
1
NAMES OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

Gabelli Group Capital Partners, Inc.
I.D. NO.  13-3056041
2
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
(a)
(b)

3
SEC USE ONLY

4
Source of funds (SEE INSTRUCTIONS)
   None

5
CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
PURSUANT TO ITEMS 2 (d) OR 2 (e)


6
CITIZENSHIP OR PLACE OF ORGANIZATION
   New York

NUMBER OF

SHARES

BENEFICIALLY

OWNED

BY EACH

REPORTING

PERSON

WITH
:
7
:
:
:
SOLE VOTING POWER

None

:
8
:
:
:
SHARED VOTING POWER

NONE

:
9
:
:
:
SOLE DISPOSITIVE POWER

NONE

:10
:
:
:
SHARED DISPOSITIVE POWER

NONE
11



AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

NONE
12



CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES
(SEE INSTRUCTIONS)
13



PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

NONE
14



TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
    HC, CO
CUSIP No. 909205106
1
NAMES OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

Gabelli Asset Management Inc.
I.D. NO.  13-4007862
2
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
(a)
(b)

3
SEC USE ONLY

4
Source of funds (SEE INSTRUCTIONS)
None

5
CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
PURSUANT TO ITEMS 2 (d) OR 2 (e)


6
CITIZENSHIP OR PLACE OF ORGANIZATION
   New York

NUMBER OF

SHARES

BENEFICIALLY

OWNED

BY EACH

REPORTING

PERSON

WITH
:
7
:
:
:
SOLE VOTING POWER

None

:
8
:
:
:
SHARED VOTING POWER

NONE

:
9
:
:
:
SOLE DISPOSITIVE POWER

NONE

:10
:
:
:
SHARED DISPOSITIVE POWER

NONE
11



AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

NONE
12



CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES
(SEE INSTRUCTIONS)
13



PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

0.00%

14



TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
    HC, CO
CUSIP No. 909205106
1
NAMES OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

Mario J. Gabelli
2
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
(a)
(b)

3
SEC USE ONLY

4
Source of funds (SEE INSTRUCTIONS)
 None

5
CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
PURSUANT TO ITEMS 2 (d) OR 2 (e)


6
CITIZENSHIP OR PLACE OF ORGANIZATION
   USA

NUMBER OF

SHARES

BENEFICIALLY

OWNED

BY EACH

REPORTING

PERSON

WITH
:
7
:
:
:
SOLE VOTING POWER

None

:
8
:
:
:
SHARED VOTING POWER

NONE

:
9
:
:
:
SOLE DISPOSITIVE POWER

NONE

:10
:
:
:
SHARED DISPOSITIVE POWER

NONE
11



AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

NONE
12



CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES
(SEE INSTRUCTIONS)
13



PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

0.00%
14



TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
    IN

Item 1.		Security and Issuer
The class of equity securities to which this statement on Schedule
13D relates are the Common Stock, no par value per share ("Securities"), of
UniSource Energy Corporation (the "Issuer"), an Arizona corporation with
principal offices located at One South Church Avenue, Suite 100, Tucson, AZ
85701.

Item 2.		Identity and Background
		This statement is being filed by Mario J. Gabelli ("Mario
Gabelli") and various entities which he directly or indirectly controls or for
which he acts as chief investment officer.  These entities, except for Lynch
Corporation ("Lynch") and Lynch Interactive Corporation ("Interactive"),
engage in various aspects of the securities business, primarily as investment
adviser to various institutional and individual clients, including registered
investment companies and pension plans, and as general partner of various
private investment partnerships.  Certain of these entities may also make
investments for their own accounts.
	The foregoing persons in the aggregate often own beneficially more than
5% of a class of a particular issuer.  Although several of the foregoing
persons are treated as institutional investors for purposes of reporting their
beneficial ownership on the short-form Schedule 13G, the holdings of those who
do not qualify as institutional investors may exceed the 1% threshold presented
for filing on Schedule 13G or implementation of their investment philosophy may
from time to time require action which could be viewed as not completely
passive.  In order to avoid any question as to whether their beneficial
ownership is being reported on the proper form and in order to provide greater
investment flexibility and administrative uniformity, these persons have
decided to file their beneficial ownership reports on the more detailed
Schedule 13D form rather than on the short-form Schedule 13G and thereby to
provide more expansive disclosure than may be necessary.
	(a), (b) and (c) - This statement is being filed by one or more of the
following persons: Gabelli Group Capital Partners, Inc. ("Gabelli Partners"),
Gabelli Asset Management Inc. ("GBL"), Gabelli Funds, LLC ("Gabelli Funds"),
GAMCO Investors, Inc. ("GAMCO"), Gabelli Advisers, Inc. ("Gabelli
Advisers"), Gabelli Securities, Inc. ("GSI"), Gabelli & Company, Inc.
("Gabelli & Company"), Gabelli & Company, Inc. Profit Sharing Plan (the
"Plan"), MJG Associates, Inc. ("MJG Associates"), Gabelli Foundation, Inc.
("Foundation"), Mario Gabelli, Lynch, and Interactive.  Those of the foregoing
persons signing this Schedule 13D are hereafter referred to as the "Reporting
Persons".
	Gabelli Partners makes investments for its own account and is the parent
company of GBL.  GBL, a public company listed on the New York Stock Exchange,
is the parent company for a variety of companies engaged in the securities
business, including those named below.
	GAMCO, a wholly-owned subsidiary of GBL, is an investment adviser
registered under the Investment Advisers Act of 1940, as amended ("Advisers
Act").  GAMCO is an investment manager providing discretionary managed account
services for employee benefit plans, private investors, endowments, foundations
and others.
	GSI, a majority-owned subsidiary of GBL, acts as a general partner or
investment manager to limited partnerships and offshore investment companies
and as a part of its business may purchase or sell securities for its own
account.  It is the immediate parent of Gabelli & Company. GSI is the
Investment Manager of Gabelli Associates Fund, Gabelli Associates Fund II,
Gabelli Associates Limited, ALCE Partners, L.P., and Gabelli Multimedia
Partners, L.P.  GSI and Marc Gabelli own 45% and 55%, respectively, of Gabelli
Securities International Limited ("GSIL"). GSIL provides investment advisory
services to offshore funds and accounts.   GSIL is an investment advisor of
Gabelli International Gold Fund Limited, Gabelli European Partners, Ltd., and
Gabelli Global Partners, Ltd.
	Gabelli & Company, a wholly-owned subsidiary of GSI, is a broker-dealer
registered under the Securities Exchange Act of 1934, as amended ("1934 Act"),
which as a part of its business regularly purchases and sells securities for
its own account.
	Gabelli Funds, a wholly owned subsidiary of GBL, is a limited liability
company. Gabelli Funds is an investment adviser registered under the Advisers
Act which presently provides discretionary managed account services for The
Gabelli Equity Trust Inc., The Gabelli Asset Fund, The Gabelli Growth Fund, The
Gabelli Convertible and Income Securities Fund, Inc., The Gabelli Value Fund
Inc., The Gabelli Small Cap Growth Fund, The Gabelli Equity Income Fund, The
Gabelli ABC Fund, The Gabelli Global Telecommunications Fund, Gabelli Gold
Fund, Inc., The Gabelli Global Multimedia Trust Inc., The Gabelli Global
Convertible Securities Fund, Gabelli Capital Asset Fund, Gabelli International
Growth Fund, Inc., The Gabelli Global Growth Fund, The Gabelli Utility Trust,
The Gabelli Global Opportunity Fund, The Gabelli Utilities Fund, The Gabelli
Blue Chip Value Fund, The Gabelli Mathers Fund, The Gabelli Woodland Small Cap
Value Fund, The Comstock Capital Value Fund and The Comstock Strategy Fund
(collectively, the "Funds"), which are registered investment companies.
	Gabelli Advisers, a subsidiary of GBL, is an investment adviser which
provides discretionary advisory services to The Gabelli Westwood Mighty Mitessm
Fund.
	The Plan, a qualified employee profit sharing plan, covers substantially
all employees of GBL and its affiliates.
	MJG Associates provides advisory services to private investment
partnerships and offshore funds.  Mario Gabelli is the sole shareholder,
director and employee of MJG Associates.   MJG Associates is the Investment
Manager of Gabelli International Limited, Gabelli International II Limited,
Gabelli Performance Partnership, and Gabelli Fund, LDC.
The Foundation is a private foundation.  Mario Gabelli is the President,
a Trustee and the Investment Manager of the Foundation.
	Lynch is a public company traded on the American Stock Exchange engaged
in manufacturing.  Interactive is a public company listed on the American Stock
Exchange and is a holding company with operating subsidiaries engaged primarily
in the rural telephone industry.  Lynch and Interactive actively pursue new
business ventures and acquisitions. Lynch and Interactive make investments in
marketable securities to preserve capital and maintain liquidity for financing
their business activities and acquisitions and are not engaged in the business
of investing, reinvesting, or trading in securities.  Mario J. Gabelli is a
director, officer and a substantial shareholder of Lynch and Interactive.
	Mario Gabelli is the majority stockholder and Chairman of the Board of
Directors and Chief Executive Officer of Gabelli Partners and GBL, and the
Chief Investment Officer for each of the Reporting Persons.  Gabelli Partners
is the majority shareholder of GBL. GBL, in turn, is the sole stockholder of
GAMCO.  GBL is also the majority stockholder of GSI and the largest shareholder
of Gabelli Advisers.  Gabelli & Company is a wholly-owned subsidiary of GSI.
	The Reporting Persons do not admit that they constitute a group.
	Gabelli Partners, GBL, GAMCO, and Gabelli & Company are New York
corporations and GSI and Gabelli Advisers are Delaware corporations, each
having its principal business office at One Corporate Center, Rye, New York
10580.  Gabelli Funds is a New York limited liability company having its
principal business office at One Corporate Center, Rye, New York 10580.  MJG
Associates is a Connecticut corporation having its principal business office at
140 Greenwich Avenue, Greenwich, CT 06830.  The Foundation is a Nevada
corporation having its principal offices at 165 West Liberty Street, Reno,
Nevada 89501.  Lynch is an Indiana corporation having its principal business
office at 50 Kennedy Plaza, Suite 1250, Providence, Rhode Island 02903.
Interactive is a Delaware corporation having its principal place of business at
One Corporate Center, Rye, New York 10580.
	For information required by instruction C to Schedule 13D with respect to
the executive officers and directors of the foregoing entities and other
related persons (collectively, "Covered Persons"), reference is made to
Schedule I annexed hereto and incorporated herein by reference.
		(f)  - Reference is made to Schedule I hereto.

Item 3.		Source and Amount of Funds or Other Consideration
		The Reporting Persons used an aggregate of approximately
$49,651,160 to purchase the Securities reported as beneficially owned in Item
5.  GAMCO and Gabelli Funds used approximately $19,480,054 and $23,752,938,
respectively, of funds that were provided through the accounts of certain of
their investment advisory clients (and, in the case of some of such accounts at
GAMCO, may be through borrowings from client margin accounts) in order to
purchase the Securities for such clients.  MJG Associates and Gabelli
Securities used approximately $49,139 and $6,123,429, respectively, of client
funds to purchase the securities reported by it.  The Foundation used
approximately $245,600 of funds from the Foundation's assets to purchase the
Securities reported by it.

Item 4.		Purpose of Transaction
		Each of the Reporting Persons has purchased and holds the
Securities reported by it for investment for one or more accounts over which it
has shared, sole, or both investment and/or voting power, for its own account,
or both.
		The Reporting Persons, with the exceptions of Lynch and its
affiliates, are engaged in the business of securities analysis and investment
and pursue an investment philosophy of identifying undervalued situations.  In
pursuing this investment philosophy, the Reporting Persons analyze the
operations, capital structure and markets of companies in which they invest,
including the Issuer, on a continuous basis through analysis of documentation
and discussions with knowledgeable industry and market observers and with
representatives of such companies (often at the invitation of management).  The
Reporting Persons do not believe they possess material inside information
concerning the Issuer.  As a result of these analytical activities one or more
of the Reporting Persons may issue analysts reports, participate in interviews
or hold discussions with third parties or with management in which the
Reporting Person may suggest or take a position with respect to potential
changes in the operations, management or capital structure of such companies as
a means of enhancing shareholder values.  Such suggestions or positions may
relate to one or more of the transactions specified in clauses (a) through (j)
of Item 4 of Schedule 13D including, without limitation, such matters as
disposing of one or more businesses, selling the company or acquiring another
company or business, changing operating or marketing strategies, adopting or
not adopting, certain types of anti-takeover measures and restructuring the
company's capitalization or dividend policy.
		Each of the Reporting Persons intends to adhere to the foregoing
investment philosophy with respect to the Issuer.  However, none of the
Reporting Persons intends to seek control of the Issuer or participate in the
management of the Issuer, and any Reporting Person that is registered as an
investment company under the 1940 Act will participate in such a transaction
only following receipt of an exemption from the SEC under Rule 17d-1 under the
1940 Act, if required, and in accordance with other applicable law.  In
pursuing this investment philosophy, each Reporting Person will continuously
assess the Issuer's business, financial condition, results of operations and
prospects, general economic conditions, the securities markets in general and
those for the Issuer's securities in particular, other developments and other
investment opportunities, as well as the investment objectives and
diversification requirements of its shareholders or clients and its fiduciary
duties to such shareholders or clients.  Depending on such assessments, one or
more of the Reporting Persons may acquire additional Securities or may
determine to sell or otherwise dispose of all or some of its holdings of
Securities.  Although the Reporting Persons share the same basic investment
philosophy and although most portfolio decisions are made by or under the
supervision of Mario Gabelli, the investment objectives and diversification
requirements of various clients differ from those of other clients so that one
or more Reporting Persons may be acquiring Securities while others are
disposing of Securities.
		With respect to voting of the Securities, the Reporting Persons
have adopted general voting policies relating to voting on specified issues
affecting corporate governance and shareholder values.  Under these policies,
the Reporting Persons generally vote all securities over which they have voting
power in favor of cumulative voting, financially reasonable golden parachutes,
one share one vote, management cash incentives and pre-emptive rights and
against greenmail, poison pills, supermajority voting, blank check preferred
stock and super-dilutive stock options.  Exceptions may be made when management
otherwise demonstrates superior sensitivity to the needs of shareholders.  In
the event that the aggregate voting position of all joint filers shall exceed
25% of the total voting position of the issuer then the proxy voting committees
of each of the Funds shall vote their Fund's shares independently.
		Each of the Covered Persons who is not a Reporting Person has
purchased the Securities reported herein as beneficially owned by him for
investment for his own account or that of one or more members of his immediate
family.  Each such person may acquire additional Securities or dispose of some
or all of the Securities reported herein with respect to him.
		Other than as described above, none of the Reporting Persons and
none of the Covered Persons who is not a Reporting Person has any present plans
or proposals which relate to or would result in any transaction, change or
event specified in clauses (a) through (j) of Item 4 of Schedule 13D.

Item 5.		Interest In Securities Of The Issuer
(a) The aggregate number and percentage of Securities to which this
Schedule 13D relates is 2,091,500 shares, representing 6.21% of the 33,675,356
shares outstanding as reported in the Issuer's most recent Form 10-Q for the
quarter ended September 30, 2003.  The Reporting Persons beneficially own those
Securities as follows:


Name

Shares of
Common Stock
% of Class of
Common
Gabelli Funds
1,015,200
3.01%

GAMCO

814,700

2.42%

Gabelli Securities

249,600

0.74%

MJG Associates

 2,000

0.01%
The Foundation
10,000
0.01%

Mario Gabelli

0

0.00%

		Mario Gabelli is deemed to have beneficial ownership of the
Securities owned beneficially by each of the foregoing persons.  GSI is deemed
to have beneficial ownership of the Securities owned beneficially by Gabelli &
Company.  GBL and Gabelli Partners are deemed to have beneficial ownership of
the Securities owned beneficially by each of the foregoing persons other than
Mario Gabelli and the Foundation.
(b) Each of the Reporting Persons and Covered Persons has the sole
power to vote or direct the vote and sole power to dispose or to direct the
disposition of the Securities reported for it, either for its own benefit or
for the benefit of its investment clients or its partners, as the case may be,
except that (i) GAMCO does not have the authority to vote 62,000 of its
reported shares, (ii) Gabelli Funds has sole dispositive and voting power with
respect to the shares of the Issuer held by the Funds so long as the aggregate
voting interest of all joint filers does not exceed 25% of their total voting
interest in the Issuer and, in that event, the Proxy Voting Committee of each
Fund shall respectively vote that Fund's shares, (iii) at any time, the Proxy
Voting Committee of each such Fund may take and exercise in its sole discretion
the entire voting power with respect to the shares held by such fund under
special  circumstances such as regulatory considerations, and (iv) the power of
Mario Gabelli, GBL, and Gabelli Partners is indirect with respect to Securities
beneficially owned directly by other Reporting Persons.
		(c) Information with respect to all transactions in the Securities
which were effected during the past sixty days or since the most recent filing
on Schedule 13D, whichever is less, by each of the Reporting Persons and
Covered Persons is set forth on Schedule II annexed hereto and incorporated
herein by reference.
		(d) The investment advisory clients of, or partnerships managed by
GAMCO, Gabelli Funds, Gabelli Advisers and MJG Associates, have the sole right
to receive and, subject to the notice, withdrawal and/or termination provisions
of such advisory contracts and partnership arrangements, the sole power to
direct the receipt of dividends from, and the proceeds of sale of, any of the
Securities beneficially owned by such Reporting Persons on behalf of such
clients or partnerships.  Except as noted, no such client or partnership has an
interest by virtue of such relationship that relates to more than 5% of the
Securities.
(e) Not applicable.



Item 6.		Contracts, Arrangements, Understandings or Relationships with
Respect
		to Securities of the Issuer
		The powers of disposition and voting of GAMCO, GSI, and MJG
Associates with respect to Securities owned beneficially by them on behalf of
their investment advisory clients, or on behalf of the partnerships which they
directly or indirectly manage, are held pursuant to written agreements with
such clients or partnerships.

Item 7.		Material to be Filed as an Exhibit
		The following Exhibit A is attached hereto.  The following Exhibit
B is incorporated by reference to Exhibit C in the Amendment No. 8 to Schedule
13D of the Reporting Persons with respect to Edgewater Technologies, Inc.
Exhibit A:


Joint Filing Agreement

Exhibit B:
Powers of Attorney to Stephen M. DeTore, Douglas R. Jamieson,
and James E. McKee from Robert E. Dolan

Powers of Attorney to Stephen M. DeTore, Douglas R. Jamieson,
and James E. McKee from Raymond H. Keller.

Powers of Attorney to Stephen M. DeTore, Douglas R. Jamieson,
and James E. McKee from Mario J. Gabelli.

Powers of Attorney to Stephen M. DeTore, Karyn M. Nappi, and
James E. McKee from Marc J. Gabelli.




Signature
	After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.
Dated:	December 29, 2003

MARIO J. GABELLI
MJG ASSOCIATES, INC.
GABELLI SECURITIES, INC
GABELLI FOUNDATION, INC.


By:/s/ James E. McKee
   James E. McKee
   Attorney-in-Fact



GABELLI GROUP CAPITAL PARTNERS, INC.
GABELLI ASSET MANAGEMENT INC.


By:/s/ James E. McKee
    James E. McKee
    Secretary



GAMCO INVESTORS, INC.



By:/s/ Douglas R. Jamieson
    Douglas R. Jamieson
    Executive Vice President



SCHEDULE I

Information with Respect to Executive
Officers and Directors of the Undersigned

Schedule I to Schedule 13D is amended, in pertinent part, as
follows:

The following sets forth as to each of the executive officers and
directors of the undersigned: his name; his business address; his
present principal occupation or employment and the name, principal
business and address of any corporation or other organization in
which such employment is conducted.  Unless otherwise specified,
the principal employer of each such individual is Gabelli Group
Capital Partners, Inc., Gabelli Asset Management Inc., Gabelli
Funds, LLC, Gabelli & Company, Inc., or GAMCO Investors, Inc., the
business address of each of which is One Corporate Center, Rye, New
York 10580, and each such individual identified below is a citizen
of the United States.  To the knowledge of the undersigned, during
the last five years, no such person has been convicted in a
criminal proceeding (excluding traffic violations or similar
misdemeanors), and no such person was a party to a civil proceeding
of a judicial or administrative body of competent jurisdiction as a
result of which he was or is subject to a judgment, decree or final
order enjoining future violations of, or prohibiting or mandating
activities subject to, federal or state securities law or finding
any violation with respect to such laws except as reported in Item
2(d) of this Schedule 13D.




Gabelli Group Capital Partners,
Inc.
Directors:

	Mario J. Gabelli

Chief Executive Officer and Chief Investment
Officer of Gabelli Group Capital Partners, Inc.,
Gabelli Asset Management Inc., and GAMCO
Investors, Inc.; Director/Trustee of all
registered investment companies advised by Gabelli
Funds, LLC; Chief Executive Officer of Lynch
Interactive Corporation; Vice Chairman of Lynch
Corporation.

	Charles C. Baum





Chairman and Director of The Morgan Group, Inc.;
Secretary & Treasurer
United Holdings Co., Inc.
2545 Wilkens Avenue
Baltimore, MD   21223


Frederic V. Salerno
Chairman
Lynch Interactive Corporation

	Arnold M. Reichman
Business Consultant

	Marc J. Gabelli

President

	Matthew R. Gabelli

Vice President - Trading
Gabelli & Company, Inc.
One Corporate Center
Rye, New York 10580
Officers:

	Mario J. Gabelli

Marc J. Gabelli

Chairman, Chief Executive Officer and Chief
Investment Officer

President
	Henry Kiernan
Vice President, Chief Financial Officer

	James E. McKee

Vice President, General Counsel and Secretary

Gabelli Asset Management
Inc.
Directors:

	Raymond C. Avansino,
Jr.
Chairman
E.L. Wiegand Foundation
165 West Liberty Street
Reno, NV 89501

	Mario J. Gabelli

See above



	Paul B. Guenther

Chairman
New York Philharmonic
10 Lincoln Center Plaza
New York, NY 10023

	John C. Ferrara
Business Consultant

	Dr. Eamon M. Kelly
Professor
Payson Center for International
Development Technology Transfer
Tulane University
300 Gibson Hall
6823 St. Charles Avenue
New Orleans, LA   70118

	Karl Otto Pohl (1)




               Frederic V.
Salerno

Sal. Oppenheim jr. & Cie.
Bockenheimer Landstrasse 20
D-6000 FRANKFURT AM MAIN
Germany

See above

Officers:

Michael R. Anastasio,
Jr.

Vice President and Chief Accounting Officer
	Mario J. Gabelli

Chairman, Chief Executive Officer and Chief
Investment Officer

	James E. McKee

Vice President, General Counsel and Secretary

GAMCO Investors, Inc.
Directors:


	Douglas R. Jamieson
	Joseph R. Rindler,
Jr.
	Regina M. Pitaro
	F. William Scholz, II
	William S. Selby


Officers:


	Mario J. Gabelli
Chief Executive Officer and Chief Investment
Officer

	Joseph R. Rindler,
Jr.
Chairman

	Douglas R. Jamieson
Executive Vice President and Chief Operating
Officer

	James E. McKee

Vice President, General Counsel and Secretary
Gabelli Funds, LLC
Officers:


	Mario J. Gabelli

Chief Investment Officer
	Bruce N. Alpert
Executive Vice President and Chief Operating
Officer

	James E. McKee
Secretary

Gabelli Advisers, Inc.
Directors:


	Bruce N. Alpert
	John D. Gabelli
	Joseph R. Rindler.
Jr.


Officers:


	Bruce N. Alpert
Chief Operating Officer

	James E. McKee
Secretary

Gabelli Securities, Inc.


Directors:


	Robert W. Blake
President of W. R. Blake & Sons, Inc.
196-20 Northern Boulevard
Flushing, NY   11358

	Douglas G. DeVivo
General Partner of ALCE Partners, L.P.
One First Street, Suite 16
Los Altos, CA   94022

	Joseph R. Rindler,
Jr.
See above

Officers:


	Michael R. Anastasio

               Thomas H. Mahoney

               James E. McKee
Vice President and Chief Accounting Officer

Vice President

Secretary

Gabelli & Company, Inc.
Directors:


	James G. Webster, III
Chairman & Interim President

	Irene Smolicz
Senior Trader
Gabelli & Company, Inc.

Officers:


	James G. Webster, III
Chairman & Interim President

	Bruce N. Alpert
Vice President - Mutual Funds

	Walter K. Walsh
Compliance Officer

	James E. McKee
Secretary


Lynch Corporation,
50 Kennedy Plaza, Suite 1250, Providence, RI 02903

Directors:


	Mario J. Gabelli
See above - Gabelli Group Capital Partners, Inc.

	Marc J. Gabelli

E. Val Cerutti
See above - Gabelli Group Capital Partners, Inc.

Business Consultant, Cerutti Consultants
227 McLain Street
Mount Kisco, NY   10540

Avrum Gray



              Ralph R. Papitto

              Richard E. McGrail

              Raymond H. Keller

              Anthony R.
Pustorino

Gbar Limited Partnership
440 South LaSalle, Suite 2900
Chicago, IL 60605

Chairman and Chief Executive Officer

President and Chief Operations Officer

Vice President and Chief Financial Officer

Professor Emeritus
Pace University
1 Martine Avenue
White Plains, NY 10606

Officers:



	Ralph R. Papitto

See above
	Mario J. Gabelli
Vice Chairman

	Richard E. McGrail
See above

	Raymond H. Keller
See above



Lynch Interactive Corporation,
401 Theodore Fremd Avenue Rye, NY 10580


Directors:


	Paul J. Evanson
President
Allegheny Energy, Inc.
10435 Downsville Pike
Hagerstown, MD 21740

	Mario J. Gabelli

Marc J. Gabelli
See above - Gabelli Group Capital Partners, Inc.

See above - Gabelli Group Capital Partners, Inc.

	Salvatore Muoio
Principal
S. Muoio & Co., LLC
Suite 406
509 Madison Ave.
New York, NY 10022

	John C. Ferrara
See above

	David C. Mitchell
Business Consultant
c/o Lynch Interactive Corporation
401 Theodore Fremd Ave.
Rye, NY 10580

	Vincent S. Tese
Lawyer, Investment Adviser and Cable Television
Executive
c/o Bear Stearns & Company, Inc.
245 Park Avenue, 19th Floor
New York, NY 10167


Frederic V. Salerno

Chairman

Officers:



	Mario J. Gabelli
Vice Chairman and Chief Executive Officer

	Robert E. Dolan

Chief Financial Officer

               John Fikre

Vice President - Corporate Development, General
Counsel, and Secretary

	(1) Citizen of Germany

                                               SCHEDULE II

                                      INFORMATION WITH RESPECT TO
                           TRANSACTIONS EFFECTED DURING THE PAST SIXTY DAYS OR
                           SINCE THE MOST RECENT FILING ON SCHEDULE 13D (1)

                                             SHARES PURCHASED        AVERAGE
                                  DATE            SOLD(-)             PRICE(2)

           COMMON STOCK-UNISOURCE ENERGY

                    GABELLI FOUNDATION, INC.
                                12/16/03            5,000            24.5300
                                12/15/03            5,000            24.5800
                                12/18/03            1,000            24.5492
                                11/28/03            1,000            24.5525
                                11/25/03            1,000            24.4730
                                11/24/03            1,000            24.5898
                    GAMCO INVESTORS, INC.
                                12/26/03           10,000            24.6000
                                12/24/03           11,700            24.5971
                                12/24/03            1,000            24.6000
                                12/24/03              700-           24.6900
                                12/24/03              700            24.6900
                                12/24/03            9,500            24.6147
                                12/23/03            1,200-           24.6300
                                12/23/03            2,700            24.6300
                                12/23/03            7,500            24.6300
                                12/23/03           12,700            24.6000
                                12/23/03              300            57.5867
                                12/23/03              700-           24.6800
                                12/23/03              800-           24.7175
                                12/23/03            3,500            24.6200
                                12/23/03              300-           57.5867
                                12/22/03           11,000            24.5282
                                12/22/03            2,000            24.5600
                                12/22/03            1,500            24.5500
                                12/22/03            5,000            24.5200
                                12/19/03            1,000            24.5673
                                12/19/03           10,000            24.5373
                                12/18/03            1,000-           24.5921
                                12/18/03           28,000            24.5921
                                12/18/03           10,000            24.4589
                                12/18/03           40,000            24.5650
                                12/18/03            1,000            24.5421
                                12/18/03            2,000            24.5500
                                12/18/03            7,500            24.5492
                                12/18/03           10,000-           24.4589
                                12/17/03            1,000            24.5880
                                12/17/03           33,000            24.6370
                                12/17/03            2,000            24.6092
                                12/16/03              300            24.7500
                                12/15/03            4,000            24.6391
                                12/15/03            4,500            24.6600
                                12/15/03            3,000            24.6100
                                12/15/03            8,500            24.5682


                     GAMCO INVESTORS, INC.
					  12/15/03            1,500            24.6591
                                12/12/03            5,000-           24.5488
                                12/12/03           10,000            24.5725
                                12/12/03            8,000             9.2058
                                12/12/03            1,000            24.6521
                                12/12/03           13,000            24.6221
                                12/12/03            2,000            24.5488
                                12/11/03            6,000            24.5775
                                12/04/03            3,000            24.7000
                                12/02/03            5,000            24.6937
                                12/02/03              700            24.7366
                                12/02/03              300            24.7937
                                12/02/03            2,000            24.7237
                                12/01/03            2,500            24.5725
                                12/01/03            1,000            24.6300
                                11/28/03            7,500            24.5847
                                11/28/03            9,000            24.5525
                                11/28/03           30,700            24.5835
                                11/26/03            5,000            24.4925
                                11/26/03           16,000            24.5767
                                11/26/03            2,000            24.5900
                                11/26/03           29,300            24.5576
                                11/25/03           10,000            24.4700
                                11/25/03           20,000            24.5256
                                11/25/03           36,500            24.4730
                                11/25/03          181,500            24.5365
                                11/25/03            7,000            24.5700
                                11/25/03            1,000            24.4900
                                11/25/03            4,000            24.5413
                                11/24/03           10,000            24.6118
                                11/24/03            3,000            24.6100
                                11/24/03            5,000            24.5990
                                11/24/03           17,000            24.5898
                                11/24/03            3,000            24.5900
                                11/24/03           95,000            24.5690
                                11/24/03            1,000            24.6118

      	    GABELLI SECURITIES INC.
                                12/18/03            1,000            24.5492
                                11/28/03            1,000            24.5525
					  11/25/03            1,000            24.4730
                                11/24/03            1,000            24.5898
                          GABELLI ASSOCIATES LTD
                                12/18/03           10,000            24.5300
                                12/17/03            5,000            24.6092
                                12/15/03           12,000            24.5682
                                12/11/03            6,000            24.5775
                                12/04/03            3,000            24.6225
                                12/03/03            2,200            24.6225
                                12/01/03            2,000            24.5725
                                11/26/03            4,000            24.4925
                                11/25/03           44,000            24.4730
                                11/24/03           15,000            24.5898
                           GAF II
                                12/18/03            1,000            24.5492
                                12/02/03            2,000            24.6225
                                11/25/03            1,600            24.4730
                                11/24/03            1,000            24.5898
                           GABELLI ASSOCIATES FUND
                                12/18/03            4,500            24.5492
                                12/18/03           10,000            24.5300
                                12/17/03            8,000            24.6092
                                12/15/03           14,500            24.5682
                          GABELLI ASSOCIATES FUND
                                12/11/03            8,000            24.5775
                                12/04/03            6,900            24.6225
                                12/02/03            1,500            24.6225
                                12/01/03            5,500            24.5725
                                11/26/03            1,000            24.4925
                                11/25/03           56,900            24.4730
                                11/24/03           20,000            24.5898
                    MJG ASSOCIATES, INC.
				GABELLI FUND, LDC
                                12/18/03            1,000            24.5492
                                11/24/03            1,000            24.5898
                     GABELLI FUNDS, LLC.
                         GABELLI MATHERS FUND
                                12/18/03            5,000            24.5800
                                12/04/03            4,000            24.7000
                                12/03/03            5,000            24.7100
                                12/02/03              700            24.7000
                                11/26/03              300            24.5900
                         GABELLI UTILITY TRUST
                                12/26/03           29,600            24.5996
                                12/18/03           61,200            24.5969
                                12/16/03           38,800            24.5639
                                11/24/03           80,000            24.6409
                         GABELLI UTILITY FUND
                                11/24/03           17,000            24.6409
                         GABELLI DIVIDEND & INCOME TRUST
                                12/22/03           50,000            24.5088
                                12/19/03            5,100            24.5200
                                12/18/03           78,600            24.5939
                                12/17/03           55,900            24.6411
                                12/16/03           18,500            24.6476
                                12/15/03          170,000            24.6417
                                12/05/03           52,100            24.7037
                                12/02/03           15,000            24.6833
                                12/01/03           47,400            24.6243
                         GABELLI CONVERTIBLE FUND
                                12/26/03           18,000            24.5996
                                12/15/03           20,000            24.6500
                         GABELLI ABC FUND
                                12/22/03           50,000            24.5400
                                11/26/03           60,000            24.6000
                                11/25/03           37,800            24.5094
                                11/24/03           52,200            24.6409


          (1) UNLESS OTHERWISE INDICATED, ALL TRANSACTIONS WERE EFFECTED
              ON THE NYSE.

          (2) PRICE EXCLUDES COMMISSION.

Exhibit A

JOINT FILING AGREEMENT

		In accordance with Rule 13d-1(f) under the Securities Exchange Act
of 1934, as amended, the undersigned hereby agree to the joint filing with all
other Reporting Entities (as such term is defined in the Schedule 13D referred
to below) on behalf of each of them of a statement on Schedule 13D (including
amendments thereto) with respect to the Common Stock, no par value, of
UniSource Energy Corporation and that this Agreement be included as an Exhibit
to such joint filing.  This Agreement may be executed in any number of
counterparts all of which taken together shall constitute one and the same
instrument.
		IN WITNESS WHEREOF, the undersigned hereby execute this agreement
this 29th day of December 2003.


MARIO J. GABELLI
GABELLI PERFORMANCE PARTNERSHIP L.P.
GABELLI INTERNATIONAL LIMITED
GABELLI INTERNATIONAL II LIMITED
GABELLI FUND, LDC
GABELLI FOUNDATION, INC.


By:/s/ James E. McKee

     James E. McKee
     Attorney-in-Fact



GABELLI GROUP CAPITAL PARTNERS, INC.
GABELLI ASSET MANAGEMENT INC.
GABELLI FUNDS, LLC
GABELLI SECURITIES, INC.
GABELLI & COMPANY, INC.


By: /s/ James E.
McKee__________________________
     James E. McKee
      Secretary

ALCE PARTNERS, L.P.
GABELLI MULTIMEDIA PARTNERS, L.P.
GABELLI EUROPEAN PARTNERS MASTER FUND, LTD.
GABELLI GLOBAL PARTNERS MASTER FUND, LTD.
GABELLI ASSOCIATES LIMITED
GABELLI ASSOCIATES FUND



By:/s/ James E. McKee
      James E. McKee
      Secretary of Gabelli Securities Inc.





LYNCH CORPORATION
BRIGHTON COMMUNICATIONS CORPORATION
LYNCH INTERACTIVE CORPORATION
WESTERN NEW MEXICO
INTER-COMMUNITY TELEPHONE COMPANY



BY:/s/ James E. McKee
___________________________
       James E. McKee
       Attorney-in-Fact



GABELLI & COMPANY, INC.
PROFIT SHARING PLAN



By:/s/ Douglas R. Jamieson

     Douglas R. Jamieson
     Trustee



GAMCO INVESTORS, INC.


By:/s/ Douglas R. Jamieson
     Douglas R. Jamieson
     Executive Vice President