munihldgins -- Converted by SEC Publisher, created by BCL Technologies Inc., for SEC Filing

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM N-Q

QUARTERLY SCHEDULE OF PORTFOLIO HOLDINGS OF REGISTERED
MANAGEMENT INVESTMENT COMPANY

  Investment Company Act file number 811-08707

Name of Fund: BlackRock MuniHoldings Insured Fund, Inc. (MUS)

Fund Address: 100 Bellevue Parkway, Wilmington, DE 19809

Name and address of agent for service: Donald C. Burke, Chief Executive Officer, BlackRock
MuniHoldings Insured Fund, Inc., 800 Scudders Mill Road, Plainsboro, NJ, 08536. Mailing
address: P.O. Box 9011, Princeton, NJ, 08543-9011

Registrant’s telephone number, including area code: (800) 882-0052, Option 4

Date of fiscal year end: 04/30/2008

Date of reporting period: 11/01/2007 – 01/31/2008

Item 1 – Schedule of Investments

BlackRock MuniHoldings Insured Fund, Inc.     
Schedule of Investments as of January 31, 2008 (Unaudited)    (in Thousands) 
 
    Face         
State    Amount    Municipal Bonds    Value 
 
 
 
Alabama - 1.3%    $ 2,170    Jefferson County, Alabama, Limited Obligation School Warrants, Series A, 5.50% due 1/01/2022    $ 2,342 
 
 
 
California - 30.7%    1,300    California State, GO, 5.50% due 4/01/2014 (f)    1,493 
    2,000    California State Public Works Board, Lease Revenue Bonds (Department of General Services - Capitol     
        East End Complex), Series A, 5% due 12/01/2027 (a)    2,045 
    5,955    California State, Various Purpose, GO, 5.25% due 12/01/2022 (d)    6,374 
    1,800    East Side Union High School District, California, Santa Clara County, GO (Election of 2002), Series B,     
        5% due 8/01/2027 (b)    1,849 
    5,155    East Side Union High School District, California, Santa Clara County, GO (Election of 2002), Series D,     
        5% due 8/01/2029 (g)    5,206 
    2,565    Modesto, California, Schools Infrastructure Financing Agency, Special Tax Bonds, 5.50%     
        due 9/01/2036 (a)    2,670 
    4,325    Palomar Pomerado Health Care District, California, GO (Election of 2004), Series A, 5.125%     
        due 8/01/2037 (e)    4,495 
    1,000    Rancho Cucamonga, California, Redevelopment Agency, Tax Allocation Refunding Bonds     
        (Rancho Redevelopment Project), Series A, 5% due 9/01/2034 (e)    1,002 
    1,265    San Jose, California, GO (Libraries, Parks and Public Safety Projects), 5% due 9/01/2030 (e)    1,303 
    2,635    San Pablo, California, Joint Powers Financing Authority, Tax Allocation Revenue Refunding Bonds, 5.66%     
        due 12/01/2024 (e)(p)    1,087 
    2,355    San Pablo, California, Joint Powers Financing Authority, Tax Allocation Revenue Refunding Bonds, 5.66%     
        due 12/01/2025 (e)(p)    912 
    2,355    San Pablo, California, Joint Powers Financing Authority, Tax Allocation Revenue Refunding Bonds, 5.66%     
        due 12/01/2026 (e)(p)    859 
    4,265    Santa Ana, California, Unified School District, GO, 5% due 8/01/2032 (e)    4,365 
    3,145    Sequoia, California, Unified High School District, GO, Refunding, Series B, 5.50% due 7/01/2035 (d)    3,427 
    4,540    Stockton, California, Public Financing Revenue Bonds (Redevelopment Projects), Series A, 5.25%     
        due 9/01/2031 (h)    4,552 
    2,180    Tustin, California, Unified School District, Senior Lien Special Tax Bonds (Community Facilities District     
        Number 97-1), Series A, 5% due 9/01/2032 (d)    2,214 
    2,800    Tustin, California, Unified School District, Senior Lien Special Tax Bonds (Community Facilities District     
        Number 97-1), Series A, 5% due 9/01/2038 (d)    2,839 
 
 
 

Portfolio Abbreviations
To simplify the listings of BlackRock MuniHoldings Insured Fund, Inc.'s portfolio holdings in the Schedule of Investments, we have abbreviated the names
of many of the securities according to the list below.

AMT    Alternative Minimum Tax (subject to)    HFA    Housing Finance Agency 
COP    Certificates of Participation    IDA    Industrial Development Authority 
DRIVERS    Derivative Inverse Tax-Exempt Receipts    M/F    Multi-Family 
EDA    Economic Development Authority    S/F    Single-Family 
GO    General Obligation Bonds    VRDN    Variable Rate Demand Notes 
HDA    Housing Development Authority         

1

BlackRock MuniHoldings Insured Fund, Inc.     
Schedule of Investments as of January 31, 2008 (Unaudited)    (in Thousands) 
 
    Face         
State    Amount    Municipal Bonds    Value 
 
 
 
    $ 3,600    Vista, California, COP (Community Projects), 5% due 5/01/2037 (e)    $ 3,616 
    3,480    West Contra Costa, California, Unified School District, GO, Series C, 5% due 8/01/2021 (b)    3,710 
 
 
 
Colorado - 6.6%    10,620    Aurora, Colorado, COP, 5.75% due 12/01/2010 (a)(f)    11,592 
 
 
 
District of Columbia - 0.9%    1,500    District of Columbia, Deed Tax Revenue Bonds (Housing Production Trust Fund - New Communities     
        Project), Series A, 5% due 6/01/2032 (e)    1,551 
 
 
 
Florida - 23.2%    1,470    Broward County, Florida, HFA, S/F Mortgage Revenue Refunding Bonds, AMT, Series E, 5.90%     
        due 10/01/2039 (n)(o)    1,607 
    2,100    Hillsborough County, Florida, HFA, S/F Mortgage Revenue Bonds, AMT, Series 1, 5.375%     
        due 10/01/2049 (n)(o)    2,200 
    3,300    Hillsborough County, Florida, IDA, Hospital Revenue Bonds (H. Lee Moffitt Cancer Center Project),     
        Series A, 5.25% due 7/01/2037    3,261 
    4,515    Jacksonville, Florida, Health Facilities Authority, Hospital Revenue Bonds (Baptist Medical Center     
        Project), 5% due 8/15/2037 (d)    4,594 
    2,500    Lee County, Florida, HFA, S/F Mortgage Revenue Bonds (Multi-County Program), AMT, Series A-2,     
        6% due 9/01/2040 (n)(o)    2,799 
    3,000    Lee Memorial Health System, Florida, Hospital Revenue Bonds, Series A, 5% due 4/01/2032 (a)    3,030 
    5,625    Miami-Dade County, Florida, Aviation Revenue Refunding Bonds (Miami International Airport), AMT,     
        Series A, 5% due 10/01/2040 (g)    5,360 
    2,225    Miami-Dade County, Florida, Special Obligation Revenue Bonds, Sub-Series A, 5.24% due 10/01/2037 (e)(p)    461 
    2,000    Miami, Florida, Special Obligation Revenue Bonds (Street and Sidewalk Improvement Program), 5%     
        due 1/01/2037 (e)    2,019 
    1,000    Okaloosa County, Florida, Water and Sewer Revenue Refunding Bonds, 5% due 7/01/2036 (d)    1,029 
    1,500    Orange County, Florida, School Board, COP, Series A, 5% due 8/01/2032 (b)    1,498 
    3,850    Pasco County, Florida, Half-Cent Sales Tax Revenue Bonds, 5.125% due 12/01/2028 (a)    3,924 
    4,295    Saint Petersburg, Florida, Public Utilities Revenue Refunding Bonds, 5% due 10/01/2035 (e)    4,397 
    2,275    South Florida Water Management District, COP, 5% due 10/01/2036 (a)    2,258 
    1,210    University of North Florida, Capital Improvement Revenue Bonds (Housing Project), 5%     
        due 11/01/2032 (b)    1,215 
    1,290    University of North Florida Financing Corporation, Capital Improvement Revenue Bonds (Housing     
        Project), 5% due 11/01/2037 (b)    1,292 
 
 
 
Georgia - 2.4%    4,000    Augusta, Georgia, Water and Sewer Revenue Bonds, 5.25% due 10/01/2034 (d)    4,232 
 
 
 
Illinois - 13.6%    7,965    Chicago, Illinois, GO, Series A, 6% due 7/01/2010 (b)(f)    8,725 
    200    Chicago, Illinois, Midway Airport Revenue Bonds, Second Lien, AMT, VRDN, Series A, 2.85%     
        due 1/01/2029 (e)(i)    200 
    1,100    Chicago, Illinois, Midway Airport Revenue Bonds, Second Lien, AMT, VRDN, Series B, 2.85%     
        due 1/01/2029 (e)(i)    1,100 
    1,000    Chicago, Illinois, O'Hare International Airport Revenue Bonds, Third Lien, Series A, 5%     
        due 1/01/2031 (e)    1,000 

2

BlackRock MuniHoldings Insured Fund, Inc.     
Schedule of Investments as of January 31, 2008 (Unaudited)    (in Thousands) 
 
    Face         
State    Amount    Municipal Bonds    Value 
 
 
 
    $ 8,000    Chicago, Illinois, O'Hare International Airport, Revenue Refunding Bonds, Series A, 5%     
        due 1/01/2033 (d)    $ 8,226 
    4,500    Illinois State, GO, First Series, 6% due 1/01/2018 (b)    4,734 
    45    Lake, Cook, Kane and McHenry Counties, Illinois, Community Unit School District Number 220, GO,     
        5.75% due 12/01/2019 (b)    48 
 
 
 
Indiana - 3.4%    6,000    Indiana Municipal Power Agency, Power Supply System Revenue Bonds, Series A, 5% due 1/01/2042 (e)    6,056 
 
 
 
Louisiana - 3.8%    6,650    Louisiana State, Gas and Fuels Tax Revenue Bonds, Series A, 5% due 5/01/2041 (b)    6,681 
 
 
 
Massachusetts - 11.6%    3,375    Massachusetts Bay Transportation Authority, Sales Tax Revenue Refunding Bonds, Senior Series A,     
        5% due 7/01/2035    3,431 
    565    Massachusetts State, HFA, Housing Development Revenue Refunding Bonds, AMT, Series A, 5.15%     
        due 6/01/2011 (e)    574 
    2,440    Massachusetts State, HFA, Rental Housing Mortgage Revenue Bonds, AMT, Series C, 5.50%     
        due 7/01/2032 (d)    2,518 
    5,600    Massachusetts State Health and Educational Facilities Authority Revenue Bonds (Lahey Clinic     
        Medical Center), Series D, 5.25% due 8/15/2037    5,654 
    8,000    Massachusetts State School Building Authority, Dedicated Sales Tax Revenue Bonds, Series A, 5%     
        due 8/15/2030 (d)    8,310 
 
 
 
Michigan - 2.3%    2,035    Boyne City, Michigan, Public School District, GO, 5.75% due 5/01/2009 (b)(f)    2,126 
    400    Michigan State Strategic Fund, Limited Obligation Revenue Refunding Bonds, DRIVERS, AMT,     
        Series 858Z, 7.111% due 12/01/2011 (g)(j)(r)    418 
    1,500    Michigan State Strategic Fund, Limited Obligation Revenue Refunding Bonds (Detroit Edison     
        Company Pollution Control Project), AMT, Series B, 5.65% due 9/01/2029 (g)    1,537 
 
 
 
Minnesota - 2.5%    4,015    Sauk Rapids, Minnesota, Independent School District Number 47, GO, Series A, 5.65% due 2/01/2019 (e)    4,342 
 
 
 
Missouri - 5.4%    2,000    Cape Girardeau, Missouri, School District Number 063, GO (Missouri Direct Deposit Program), 5.50%     
        due 3/01/2018 (b)    2,110 
    5,510    Mehlville, Montana, School District Number R-9, COP, Series A, 5.50% due 3/01/2011 (d)(f)    6,006 
    360    Mehlville, Montana, School District Number R-9, COP, Series A, 5.50% due 3/01/2014 (d)    390 
    405    Mehlville, Montana, School District Number R-9, COP, Series A, 5.50% due 3/01/2015 (d)    438 
    215    Mehlville, Montana, School District Number R-9, COP, Series A, 5.50% due 3/01/2016 (d)    233 
    280    Mehlville, Montana, School District Number R-9, COP, Series A, 5.50% due 3/01/2017 (d)    302 
 
 
 
New Jersey - 9.5%    3,800    New Jersey EDA, Cigarette Tax Revenue Bonds, 5.75% due 6/15/2034 (l)    4,080 
    6,700    New Jersey EDA, Motor Vehicle Surcharge Revenue Bonds, Series A, 5.25% due 7/01/2033 (e)    6,924 
    5,500    New Jersey State Turnpike Authority, Turnpike Revenue Bonds, Series C, 5% due 1/01/2030 (d)    5,715 
 
 
 
New York - 16.6%    10,000    Nassau Health Care Corporation, New York, Health System Revenue Bonds, 5.75% due 8/01/2009 (d)(f)    10,738 
    4,000    New York City, New York, GO, Series E, 5% due 11/01/2017 (d)    4,418 
    4,095    New York City, New York, Sales Tax Asset Receivable Corporation Revenue Bonds, Series A, 5.25%     
        due 10/15/2027 (a)    4,346 
    4,000    New York City, New York, Sales Tax Asset Receivable Corporation Revenue Bonds, Series A, 5%     
        due 10/15/2032 (a)    4,138 

3

BlackRock MuniHoldings Insured Fund, Inc.     
Schedule of Investments as of January 31, 2008 (Unaudited)    (in Thousands) 
 
    Face         
State    Amount    Municipal Bonds    Value 
 
 
 
    $ 1,800    New York State Dormitory Authority, Non-State Supported Debt Revenue Bonds (New York     
        University), Series A, 5% due 7/01/2032 (a)    $ 1,870 
    3,505    New York State Dormitory Authority Revenue Bonds (School Districts Financing Program), Series D,     
        5.25% due 10/01/2023 (e)    3,726 
 
 
 
Oregon - 0.8%    1,400    Portland, Oregon, Urban Renewal and Redevelopment Tax Allocation Bonds (Oregon Convention     
        Center), Series A, 5.75% due 6/15/2015 (a)    1,504 
 
 
 
Pennsylvania - 2.2%    3,900    Pennsylvania State Higher Educational Facilities Authority, State System of Higher Education Revenue     
        Bonds, Series O, 5.125% due 6/15/2024 (a)    3,905 
 
 
 
Rhode Island - 4.7%    5,000    Providence, Rhode Island, Redevelopment Agency Revenue Refunding Bonds (Public Safety and     
        Municipal Buildings), Series A, 5.75% due 4/01/2010 (a)(f)    5,407 
    2,870    Rhode Island State Health and Educational Building Corporation Revenue Bonds (Rhode Island School     
        of Design), Series D, 5.50% due 8/15/2031 (g)    2,959 
 
 
 
South Carolina - 7.9%    1,525    Medical University Hospital Authority, South Carolina, Hospital Facilities Revenue Refunding Bonds,     
        Series A, 5.25% due 2/15/2025 (c)(e)    1,587 
    2,000    South Carolina Jobs EDA, Hospital Revenue Bonds (Oconee Memorial Hospital Project), VRDN,     
        Series A, 6% due 10/01/2036 (h)(i)    2,000 
    10,000    South Carolina State Public Service Authority, Revenue Refunding Bonds, Series A, 5% due 1/01/2042 (a)    10,253 
 
 
 
Tennessee - 4.6%    1,665    Blount County, Tennessee, Public Building Authority, Local Government Public Improvement Revenue     
        Bonds, VRDN, Series A-1-C, 6% due 6/01/2017 (a)(i)    1,665 
    1,600    Blount County, Tennessee, Public Building Authority, Local Government Public Improvement Revenue     
        Bonds, VRDN, Series A-1-E, 6% due 6/01/2022 (a)(i)    1,600 
    455    Blount County, Tennessee, Public Building Authority, Local Government Public Improvement Revenue     
        Bonds, VRDN, Series A-5-B, 5% due 6/01/2028 (a)(i)    455 
    2,300    Tennessee HDA, Revenue Refunding Bonds (Homeownership Program), AMT, Series A, 5.25%     
        due 7/01/2022 (d)    2,336 
    2,115    Tennessee HDA, Revenue Refunding Bonds (Homeownership Program), AMT, Series A, 5.35%     
        due 1/01/2026 (d)    2,138 
 
 
 
Texas - 1.6%    2,651    Houston, Texas, Community College System, Participation Interests, COP (Alief Center Project), 5.75%     
        due 8/15/2022 (e)    2,737 
 
 
 
Virginia - 0.9%    1,500    Virginia State, HDA, Commonwealth Mortgage Revenue Bonds, Series H, Sub-Series H-1, 5.35%     
        due 7/01/2031 (e)    1,525 
 
 
 
Washington - 4.9%    4,000    Bellevue, Washington, GO, Refunding, 5.50% due 12/01/2039 (e)    4,258 
    2,310    Chelan County, Washington, Public Utility District Number 001, Consolidated Revenue Bonds     
        (Chelan Hydro System), AMT, Series A, 5.45% due 7/01/2037 (a)    2,350 
    1,810    Snohomish County, Washington, Public Utility District Number 001, Electric Revenue Bonds, 5.50%     
        due 12/01/2022 (d)    1,962 
 
 
 
West Virginia - 2.9%    5,000    West Virginia State Housing Development Fund, Housing Finance Revenue Refunding Bonds,     
        Series D, 5.20% due 11/01/2021 (e)    5,127 
 
 
 

4

BlackRock MuniHoldings Insured Fund, Inc.     
Schedule of Investments as of January 31, 2008 (Unaudited)    (in Thousands) 
 
    Face         
State    Amount    Municipal Bonds    Value 
 
 
 
Wisconsin - 0.3%    $ 500    Wisconsin State Health and Educational Facilities Authority Revenue Bonds (Blood Center of     
        Southeastern Wisconsin Project), 5.50% due 6/01/2024    $ 519 
 
 
 
Puerto Rico - 1.8%    300    Puerto Rico Commonwealth, Public Improvement, GO, Refunding, Series B, 5.25% due 7/01/2032    298 
    1,000    Puerto Rico Electric Power Authority, Power Revenue Bonds, Series TT, 5% due 7/01/2037    992 
    1,870    Puerto Rico Public Buildings Authority, Government Facilities Revenue Refunding Bonds, Series D,     
        5.25% due 7/01/2036    1,845 
 
 
 
        Total Municipal Bonds (Cost - $287,625) - 166.4%    293,215 
 
 
 
        Municipal Bonds Transferred to Tender Option Bond Trusts (q)     
 
 
 
Arkansas - 4.3%    7,420    Arkansas State Development Finance Authority, M/F Mortgage Revenue Refunding Bonds, Series C, 5.35% due     
        12/01/2035 (c)(e)    7,525 
 
 
 
Illinois - 2.6%    4,300    Chicago, Illinois, O'Hare International Airport Revenue Bonds, Third Lien, AMT, Series B-2, 6%     
        due 1/01/2029 (e)    4,555 
 
 
 
Michigan - 2.7%    1,200    Michigan State Strategic Fund, Limited Obligation Revenue Refunding Bonds (Detroit Edison Company     
        Pollution Control Project), AMT, Series A, 5.50% due 6/01/2030 (g)    1,227 
    3,500    Michigan State Strategic Fund, Limited Obligation Revenue Refunding Bonds (Detroit Edison Company     
        Pollution Control Project), AMT, Series C, 5.65% due 9/01/2029 (g)    3,587 
 
 
 
Texas - 4.6%    8,000    Dallas-Fort Worth, Texas, International Airport Revenue Bonds, AMT, Series A, 5.50%, due 11/1/2033 (e)    8,137 
 
 
 
        Total Municipal Bonds Transferred to Tender Option Bond Trusts (Cost - $25,879) - 14.2%    25,031 
 
 
 
    Shares         
    Held    Short-Term Securities     
 
 
 
    1,021    Merrill Lynch Institutional Tax-Exempt Fund, 2.47% (k)(m)    1,021 
 
 
 
        Total Short-Term Securities (Cost - $1,021) - 0.6%    1,021 
 
 
 
        Total Investments (Cost - $314,525*) - 181.2%    319,267 
        Other Assets Less Liabilities - 1.9%    3,259 
        Liability for Trust Certificates, Including Interest Expense Payable - (7.0%)    (12,301) 
        Preferred Stock, at Redemption Value - (76.1%)    (134,054) 
           
        Net Assets Applicable to Common Stock - 100.0%    $ 176,171 
           

*    The cost and unrealized appreciation (depreciation) of investments as of January 31, 2008, as computed for federal 
    income tax purposes, were as follows:     
    Aggregate cost    $ 302,454 
       
    Gross unrealized appreciation    $ 6,627 
    Gross unrealized depreciation    (2,024) 
       
    Net unrealized appreciation    $ 4,603 
       

5

BlackRock MuniHoldings Insured Fund, Inc.
Schedule of Investments as of January 31, 2008 (Unaudited)

(in Thousands)

(a)      AMBAC Insured.
 
(b)      FGIC Insured.
 
(c)      FHA Insured.
 
(d)      FSA Insured.
 
(e)      MBIA Insured.
 
(f)      Prerefunded.
 
(g)      XL Capital Insured.
 
(h)      Radian Insured.
 
(i)      Variable rate security. Rate shown is interest rate as of the report date.
 
(j)      The rate disclosed is that currently in effect. This rate changes periodically and inversely based upon prevailing market rates.
 
(k)      Investments in companies considered to be an affiliate of the Fund, for purposes of Section 2(a)(3) of the Investment
 
Company Act of 1940, were as follows:         
 
 
    Net    Dividend 
Affiliate    Activity    Income 
 
 
Merrill Lynch Institutional Tax-Exempt Fund    1    $5 
 
 

(l)      Assured Guaranty Insured.
 
(m)      Represents the current yield as of January 31, 2008.
 
(n)      FHLMC Collateralized.
 
(o)      FNMA/GNMA Collateralized.
 
(p)      Represents a zero coupon bond; the interest rate shown reflects the effective yield at the time of purchase.
 
(q)      Securities represent underlying bonds transferred to a separate securitization trust established in a tender option bond transaction in which the Fund may have acquired the residual interest certificates. These securities serve as collateral in a financing transaction.
 
(r)      These securities are short-term floating rate certificates issued by the tender option bond trust and are secured by the underlying municipal bond securities.
 

6

Item 2 – Controls and Procedures

2(a) – The registrant’s principal executive and principal financial officers or persons performing
similar functions have concluded that the registrant’s disclosure controls and procedures (as
defined in Rule 30a-3(c) under the Investment Company Act of 1940, as amended (the
“1940 Act”)) are effective as of a date within 90 days of the filing of this report based on the
evaluation of these controls and procedures required by Rule 30a-3(b) under the 1940 Act
and Rule 13a-15(b) under the Securities Exchange Act of 1934, as amended.

2(b) – There were no changes in the registrant’s internal control over financial reporting (as
defined in Rule 30a-3(d) under the 1940 Act) that occurred during the registrant’s last fiscal
quarter that have materially affected, or are reasonably likely to materially affect, the
registrant’s internal control over financial reporting.

Item 3 – Exhibits

  Certifications – Attached hereto

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment
Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by
the undersigned, thereunto duly authorized.

BlackRock MuniHoldings Insured Fund, Inc.

By: /s/ Donald C. Burke

  Donald C. Burke
Chief Executive Officer of
BlackRock MuniHoldings Insured Fund, Inc.

  Date: March 24, 2008

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment
Company Act of 1940, this report has been signed below by the following persons on behalf
of the registrant and in the capacities and on the dates indicated.

  By: /s/ Donald C. Burke
Donald C. Burke
Chief Executive Officer (principal executive officer) of
BlackRock MuniHoldings Insured Fund, Inc.

  Date: March 24, 2008

  By: /s/ Neal J. Andrews
Neal J. Andrews
Chief Financial Officer (principal financial officer) of
BlackRock MuniHoldings Insured Fund, Inc.

Date: March 24, 2008