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UNITEDSTATES
SECURITIESANDEXCHANGECOMMISSION
Washington,D.C.20549

FORM N-Q

QUARTERLY SCHEDULE OF PORTFOLIO HOLDINGS OF REGISTERED
MANAGEMENT INVESTMENT COMPANY

Investment Company Act file number 811-07156

Name of Fund: BlackRock MuniYield Insured Investment Fund (MFT)

Fund Address: 100 Bellevue Parkway, Wilmington, DE 19809

Name and address of agent for service: Anne F. Ackerley, Chief Executive Officer, BlackRock
MuniYield Insured Investment Fund, 55 East 52nd Street, New York, NY 10055.

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

Date of fiscal year end: 07/31/2010

Date of reporting period: 10/31/2009

Item 1 – Schedule of Investments

BlackRock MuniYield Insured Investment Fund (MFT)       
Schedule of Investments October 31, 2009 (Unaudited)  (Percentages shown are based on Net Assets) 
      Par   
State  Municipal Bonds    (000)  Value 
Alabama - 4.2%         
Health - 4.2%  Birmingham Alabama Special Care Facilities Financing Authority,     
  RB, Health Care Facilities, Children's Hospital (AGC), 6.00%,     
  6/01/39    $ 2,985 $  3,167,025 
  Birmingham Special Care Facilities Financing Authority, RB,     
  Childrens Hospital (AGC), 6.13%, 6/01/34               1,500  1,611,825 
  Total Municipal Bonds in Alabama      4,778,850 
California - 2.2%         
Transportation - 1.3%  County of Sacramento California, RB, Senior, Series A (AGC),     
  5.50%, 7/01/41               1,400  1,468,026 
Utilities - 0.9%  San Diego Public Facilities Financing Authority, RB,     
  Series B (AGC), 5.38%, 8/01/34               1,020  1,072,479 
  Total Municipal Bonds in California      2,540,505 
Colorado - 1.2%         
Health - 1.2%  Colorado Health Facilities Authority, RB, Hospital, NCMC Inc.,     
  Project, Series B (FSA), 6.00%, 5/15/26               1,300  1,425,567 
  Total Municipal Bonds in Colorado      1,425,567 
Florida - 63.8%         
County/City/Special  City of Jacksonville Florida, Refunding RB & Improvement (MBIA),     
District/School  5.25%, 10/01/32               1,455  1,469,419 
District - 21.7%  City of Orlando Florida, RB, Senior, 6th Cent Contract Payments,     
  Series A (AGC), 5.25%, 11/01/38               1,440  1,445,602 
  County of Lee Florida, RB (AMBAC), 5.25%, 10/01/23             1,000  1,027,390 
  County of Miami-Dade Florida, RB, CAB, Sub-Series A (MBIA),     
  5.19%, 10/01/31 (a)               4,375  1,002,094 
  County of Miami-Dade Florida, RB, CAB, Sub-Series A (MBIA),     
  5.20%, 10/01/33 (a)               5,735  1,136,448 
  County of Orange Florida, Refunding RB (AMBAC),       
  5.00%, 10/01/29               2,190  2,230,318 
  County of Orange Florida, Refunding RB, Series A (MBIA),     
  5.13%, 1/01/23               1,000  1,028,430 
  County of Osceola Florida, RB, Series A (MBIA), 5.50%, 10/01/27             1,100  1,121,296 
  County of Palm Beach Florida, RB (MBIA), 7.20%, 6/01/15             1,500  1,791,675 
Portfolio Abbreviations         

To simplify the listings of portfolio holdings in the Schedule of Investments, the names and descriptions of many of the
securities have been abbreviated according to the following list.

AGC  Assured Guaranty Corp.  GO  General Obligation Bonds 
AMBAC  American Municipal Bond Assurance Corp.  HFA  Housing Finance Authority 
AMT  Alternative Minimum Tax (subject to)  IDA  Industrial Development Authority 
CAB  Capital Appreciation Bonds  MBIA  Municipal Bond Investors Assurance 
CIFG  CDC IXIS Financial Guaranty    (National Public Finance Guaranty 
COP  Certificates of Participation    Corp.) 
EDA  Economic Development Authority  RB  Revenue Bonds 
FGIC  Financial Guaranty Insurance Co.  S/F  Single-Family 
FSA  Financial Security Assurance Inc.     
GNMA  Government National Mortgage Association     

1

BlackRock MuniYield Insured Investment Fund (MFT)       
Schedule of Investments October 31, 2009 (Unaudited)  (Percentages shown are based on Net Assets) 
      Par   
State  Municipal Bonds    (000)  Value 
  Miami-Dade County IDA, RB, BAC Funding Corp. Project,     
  Series A (AMBAC), 5.38%, 10/01/30    $ 1,655 $  1,700,132 
  Palm Beach County School Board, Florida, COP, Series D (FSA),     
  5.25%, 8/01/21    2,000  2,119,040 
  Santa Rosa County School Board, COP, Series 2 (MBIA),     
  5.25%, 2/01/26    2,000  2,074,200 
  Village Center Community Development District Recreational     
  Revenue, RB, Series A (MBIA), 5.38%, 11/01/34    1,640  1,502,191 
  Village Center Community Development District Recreational     
  Revenue, RB, Series A (MBIA), 5.13%, 11/01/36    1,000  871,710 
  Village Center Community Development District Utility Revenue, RB     
  (MBIA), 5.25%, 10/01/23    1,310  1,290,887 
  Village Center Community Development District Utility Revenue, RB     
  (MBIA), 5.13%, 10/01/28    3,030  2,931,858 
        24,742,690 
Education - 7.3%  Broward County Educational Facilities Authority, RB, Educational     
  Facilities, Nova Southeastern (AGC), 5.00%, 4/01/31  1,720  1,724,610 
  Orange County Educational Facilities Authority, RB, Rollins College     
  Project (AMBAC), 5.50%, 12/01/32    4,765  4,795,877 
  Volusia County IDA, RB, Student Housing, Stetson University     
  Project, Series A (CIFG), 5.00%, 6/01/25    1,000  898,670 
  Volusia County IDA, RB, Student Housing, Stetson University     
  Project, Series A (CIFG), 5.00%, 6/01/35    1,000  861,840 
        8,280,997 
Health - 2.5%  Jacksonville Economic Development Commission, RB, Mayo Clinic,     
  Series B (MBIA), 5.50%, 11/15/36    750  760,860 
  Orange County Health Facilities Authority, RB, Hospital, Orlando     
  Regional Healthcare, 6.00%, 12/01/12 (b)    1,835  2,096,414 
        2,857,274 
Housing - 2.2%  Florida HFA, RB, Housing, Brittany Rosemont Apartments,     
  Series C-1, AMT (AMBAC), 6.75%, 8/01/14    780  781,334 
  Florida Housing Finance Corp., RB, Homeowner Mortgage,     
  Series 4, AMT (FSA), 6.25%, 7/01/22    240  245,030 
  Florida Housing Finance Corp., RB, Homeowner Mortgage,     
  Series 11, AMT (FSA), 5.95%, 1/01/32    1,485  1,486,544 
        2,512,908 
State - 5.7%  Florida State Board of Education, RB, Series A (FGIC),     
  6.00%, 7/01/10 (b)    6,190  6,484,087 
Transportation - 13.4%  County of Lee Florida, RB, Series A, AMT (FSA), 6.00%, 10/01/29  1,000  1,012,380 
  County of Miami-Dade Florida, RB, Miami International Airport,     
  Series A, AMT (FSA), 5.25%, 10/01/41    1,200  1,165,764 
  County of Miami-Dade Florida, RB, Miami International Airport,     
  Series A, AMT (FSA), 5.50%, 10/01/41    2,400  2,410,128 
  County of Miami-Dade Florida, RB, Series A, AMT (FSA),     
  5.00%, 10/01/33    4,505  4,241,322 

2

BlackRock MuniYield Insured Investment Fund (MFT)       
Schedule of Investments October 31, 2009 (Unaudited)  (Percentages shown are based on Net Assets) 
      Par   
State  Municipal Bonds    (000)  Value 
  Hillsborough County Aviation Authority, Florida, RB,     
  Series C, AMT (AGC), 5.75%, 10/01/26    $ 1,000 $  1,033,760 
  Jacksonville Port Authority, RB, AMT (MBIA), 5.63%, 11/01/26  1,225  1,226,360 
  Miami-Dade County Expressway Authority, Florida, RB,     
  Series B (MBIA), 5.25%, 7/01/27    1,000  1,020,650 
  Orlando & Orange County Expressway Authority, RB,     
  Series B (AMBAC), 5.00%, 7/01/35    3,190  3,113,185 
        15,223,549 
Utilities - 11.0%  City of Boynton Beach Florida, RB (FGIC), 6.25%, 11/01/20 (c)  700  849,919 
  City of Lakeland Florida, Refunding RB, Series A (MBIA),     
  5.00%, 10/01/28    1,500  1,510,020 
  City of Miami Beach Florida, RB, Water And Sewer Revenue     
  (AMBAC), 5.75%, 9/01/25    2,000  2,059,600 
  City of Panama City Florida, RB, Series B (MBIA), 5.25%, 10/01/22  1,500  1,533,825 
  City of Port Saint Lucie Florida, RB (MBIA), 5.25%, 9/01/24  1,055  1,077,028 
  County of Polk Florida, RB (MBIA), 5.25%, 10/01/22  1,000  1,018,360 
  County of Saint John's Florida, RB (FSA), 5.00%, 10/01/31  2,425  2,464,528 
  Emerald Coast Utilities Authority, RB, System (MBIA),     
  5.25%, 1/01/36    1,000  1,000,970 
  Saint Lucie West Services District, RB (MBIA), 5.25%, 10/01/34  1,000  1,004,500 
        12,518,750 
  Total Municipal Bonds in Florida      72,620,255 
Georgia - 2.8%         
County/City/Special  Metropolitan Atlanta Rapid Transit Authority, Refunding RB, Third     
District/School  Indenture, Series B (FSA), 5.00%, 7/01/34    2,100  2,179,758 
District - 1.9%         
Utilities - 0.9%  County of Fulton Georgia, RB (MBIA), 5.25%, 1/01/35  1,000  1,021,680 
  Total Municipal Bonds in Georgia      3,201,438 
Illinois - 4.5%         
County/City/Special  Chicago Board of Education, Illinois, GO, Chicago School Reform     
District/School  Board, Series A (MBIA), 5.50%, 12/01/26    825  902,913 
District - 0.8%         
Transportation - 1.4%  Chicago Transit Authority, RB, Federal Transit Administration     
  Section 5309, Series A (AGC), 6.00%, 6/01/26    1,400  1,588,664 
Utilities - 2.3%  City of Chicago Illinois, Refunding RB, Second Lien (MBIA),     
  5.50%, 1/01/30    895  965,642 
  Illinois Municipal Electric Agency, RB, Series A (MBIA),     
  5.25%, 2/01/28    1,565  1,626,035 
        2,591,677 
  Total Municipal Bonds in Illinois      5,083,254 
Indiana - 3.5%         
Utilities - 3.5%  Indianapolis Local Public Improvement Bond Bank, RB, Waterworks     
  Project, Series A (AGC), 5.50%, 1/01/38    2,310  2,471,076 

3

BlackRock MuniYield Insured Investment Fund (MFT)       
Schedule of Investments October 31, 2009 (Unaudited)  (Percentages shown are based on Net Assets) 
      Par   
State  Municipal Bonds    (000)  Value 
  Indiana Municipal Power Agency, Indiana, RB, Series A (MBIA),     
  5.00%, 1/01/42  $ 1,485 $  1,466,170 
  Total Municipal Bonds in Indiana      3,937,246 
Iowa - 1.1%         
Health - 1.1%  Iowa Finance Authority, RB, Iowa Health System (AGC),     
  5.25%, 2/15/29    1,190  1,210,028 
  Total Municipal Bonds in Iowa      1,210,028 
Kentucky - 0.9%         
Utilities - 0.9%  Kentucky Municipal Power Agency, RB, Prairie State Project,     
  Series A (MBIA), 5.25%, 9/01/42    1,000  1,027,720 
  Total Municipal Bonds in Kentucky      1,027,720 
Louisiana - 1.9%         
State - 1.4%  Louisiana State Citizens Property Insurance Corp., RB,     
  Series C-3 (AGC), 6.13%, 6/01/25    1,405  1,561,714 
Transportation - 0.5%  New Orleans Aviation Board, Louisiana, Refunding RB, Restructuring     
  Garbs, Series A-1 (AGC), 6.00%, 1/01/23    375  418,946 
  New Orleans Aviation Board, Louisiana, Refunding RB, Restructuring     
  Garbs, Series A-2 (AGC), 6.00%, 1/01/23    160  178,750 
        597,696 
  Total Municipal Bonds in Louisiana      2,159,410 
Michigan - 16.6%         
County/City/Special  Michigan State Building Authority, Refunding RB, Facilities Program,     
District/School  Series I (AGC), 5.25%, 10/15/22    1,350  1,447,659 
District - 1.3%         
Health - 1.3%  Royal Oak Hospital Finance Authority, Michigan, RB, William     
  Beaumont Hospital, 8.25%, 9/01/39    1,265  1,469,158 
State - 0.8%  Michigan State Building Authority Refunding RB, Facilities Program,     
  Series I (AGC), 5.25%, 10/15/24    616  648,850 
  Michigan State Building Authority Refunding RB, Facilities Program,     
  Series I (AGC), 5.25%, 10/15/25    310  324,988 
        973,838 
Utilities - 13.2%  City of Detroit Michigan, RB, Second Lien, Series B (FSA),     
  6.25%, 7/01/36    1,800  1,936,386 
  City of Detroit Michigan, RB, Second Lien, Series B (FSA),     
  7.00%, 7/01/36    200  234,718 
  City of Detroit Michigan, RB, Second Lien, Series B (MBIA),     
  5.50%, 7/01/29    1,640  1,645,297 
  City of Detroit Michigan, RB, Second Lien, Series E (FGIC),     
  5.75%, 7/01/31    2,270  2,439,637 
  City of Detroit Michigan, RB, Senior Lien, Series B,       
  5.50%, 7/01/35    3,750  3,872,325 
  City of Detroit Michigan, RB, Senior Lien, Series B (FSA),     
  7.50%, 7/01/33    475  586,530 
  City of Detroit Michigan, RB, System, Second Lien,       
  Series A (FGIC), 5.50%, 7/01/36    2,265  2,351,795 

4

BlackRock MuniYield Insured Investment Fund (MFT)       
Schedule of Investments October 31, 2009 (Unaudited)  (Percentages shown are based on Net Assets) 
      Par   
State  Municipal Bonds    (000)  Value 
  City of Detroit Michigan, Refunding RB, Senior Lien,     
  Series C-1 (FSA), 7.00%, 7/01/27    $ 1,650 $  2,012,455 
        15,079,143 
  Total Municipal Bonds in Michigan      18,969,798 
Minnesota - 3.0%         
Health - 3.0%  City of Minneapolis Minnesota, RB, Fairview Health Services,     
  Series B (AGC), 6.50%, 11/15/38    3,000  3,377,490 
  Total Municipal Bonds in Minnesota      3,377,490 
New Jersey - 3.7%         
Health - 1.3%  New Jersey Health Care Facilities Financing Authority, RB, Virtual     
  Health (AGC), 5.50%, 7/01/38    1,400  1,445,458 
Housing - 1.4%  New Jersey State Housing & Mortgage Finance Agency, RB, S/F     
  Housing, Series CC, 5.25%, 10/01/29    1,615  1,660,850 
State - 1.0%  New Jersey EDA, RB, School Facilities Construction,     
  Series Z (AGC), 6.00%, 12/15/34    1,000  1,117,130 
  Total Municipal Bonds in New Jersey      4,223,438 
New York - 5.8%         
County/City/Special  New York City Transitional Finance Authority, RB, Fiscal 2009,     
District/School  Series S-3, 5.25%, 1/15/39    1,000  1,038,380 
District - 2.8%  New York City Transitional Finance Authority, RB, Fiscal 2009,     
  Series S-4 (AGC), 5.50%, 1/15/29    2,000  2,172,840 
        3,211,220 
State - 3.0%  New York State Dormitory Authority, RB, Education,     
  Series B, 5.25%, 3/15/38    3,250  3,401,678 
  Total Municipal Bonds in New York      6,612,898 
Pennsylvania - 1.3%         
Transportation - 1.3%  Pennsylvania Turnpike Commission, RB, Sub-Series B (FSA),     
  5.25%, 6/01/39    1,455  1,447,565 
  Total Municipal Bonds in Pennsylvania      1,447,565 
Puerto Rico - 1.3%         
State - 1.3%  Puerto Rico Sales Tax Financing Corp., RB, First       
  Sub-Series A, 6.38%, 8/01/39    1,425  1,536,977 
  Total Municipal Bonds in Puerto Rico      1,536,977 
Texas - 12.2%         
County/City/Special  City of Dallas Texas, Refunding RB & Improvement (AGC),     
District/School  5.25%, 8/15/38    850  867,553 
District - 1.23%  Lubbock Copper Texas Independent School District, GO, School     
  Building (AGC), 5.75%, 2/15/42    500  529,425 
        1,396,977 
Health - 1.6%  Harris County Health Facilities Development Corp., Refunding RB,     
  Memorial Hermann Healthcare System, Series B, 7.25%, 12/01/35  500  558,850 
  Tarrant County Cultural Education Facilities Finance Corp.,     
  Refunding RB, Christus Health, Series A (AGC), 6.50%, 7/01/37  1,100  1,208,196 
        1,767,046 
Transportation - 2.7%  North Texas Tollway Authority, Refunding RB, System, First Tier,     
  Series A (AGC), 5.75%, 1/01/40    1,500  1,577,655 

5

BlackRock MuniYield Insured Investment Fund (MFT)       
Schedule of Investments October 31, 2009 (Unaudited)  (Percentages shown are based on Net Assets) 
      Par   
State  Municipal Bonds    (000)  Value 
  North Texas Tollway Authority, Refunding RB, System, First Tier,     
  Series K-1 (AGC), 5.75%, 1/01/38    $ 1,400 $  1,482,698 
        3,060,353 
Utilities - 6.7%  City of Houston Texas, Refunding RB, Combined, First Lien,     
  Series A (AGC), 6.00%, 11/15/35    2,700  3,069,252 
  City of Houston Texas, Refunding RB, Combined, First Lien,     
  Series A (AGC), 6.00%, 11/15/36    2,055  2,338,199 
  City of Houston Texas, Refunding RB, First Lien, Series A (AGC),     
  5.38%, 11/15/38    1,000  1,056,920 
  Lower Colorado River Authority, Refunding RB, LCRA (AGC),     
  5.50%, 5/15/36    1,155  1,204,607 
        7,668,978 
  Total Municipal Bonds in Texas      13,893,355 
Utah - 1.4%         
Health - 1.4%  City of Riverton Utah, RB, IHC Health Services Inc.,     
  5.00%, 8/15/41    1,670  1,618,197 
  Total Municipal Bonds in Utah      1,618,197 
Virginia - 1.1%         
State - 1.1%  Virginia Public School Authority, Virginia, RB, School Financing,     
  6.50%, 12/01/35    1,100  1,264,307 
  Total Municipal Bonds in Virginia      1,264,307 
  Total Municipal Bonds - 132.5%      150,928,298 
  Municipal Bonds Transferred to Tender Option Bond Trusts (d)     
District of         
Columbia - 0.8%         
Utilities - 0.8%  District of Columbia Water & Sewer Authority, RB,     
  Series A, 6.00%, 10/01/35    750  838,421 
Florida - 17.3%         
County/City/Special  City of Jacksonville, Florida, RB, Better Jacksonville (MBIA), 5.00%,     
District/School  10/01/27    1,320  1,348,182 
District - 1.2%         
Transportation - 2.2%  Hillsborough County Aviation Authority, Florida, RB,     
  Series A, AMT (AGC), 5.50%, 10/01/38    2,499  2,513,153 
Health - 10.6%  Miami Dade County Health Facilities Authority, Florida, Refunding     
  RB, Miami Children's Hospital, Series A (AMBAC), 5.63%, 8/15/11  6,960  7,617,824 
  South Broward Hospital District, Florida, RB (MBIA),     
  5.63%, 5/01/12    4,000  4,455,680 
        12,073,504 
Housing - 2.2%  Lee County HFA, RB, Multi-County Program, Series A-2, AMT     
  (GNMA), 6.00%, 9/01/40    1,455  1,560,982 
  Manatee County HFA, RB, Series A, AMT (GNMA), 5.90%, 9/01/40  911  927,468 
        2,488,450 
Utilities - 1.1%  Jacksonville Electric Authority, RB, River Power Park, Issue Three,     
  Series 2, 5.00%, 10/01/37    1,290  1,291,613 
        19,714,902 

6

BlackRock MuniYield Insured Investment Fund (MFT)       
Schedule of Investments October 31, 2009 (Unaudited)  (Percentages shown are based on Net Assets) 
      Par   
State  Municipal Bonds Transferred to Tender Option Bond Trusts (d)  (000)  Value 
Kentucky - 1.0%         
State - 1.0%  Kentucky State Property & Buildings Commission, Kentucky,     
  Refunding RB, Project No. 93 (AGC), 5.25%, 2/01/27  $ 1,002 $  1,073,879 
Nevada - 3.8%         
County/City/Special  Clark County Water Reclamation District, GO, Limited Tax,     
District/School  6.00%, 7/01/38    2,010  2,206,156 
District - 3.8%  Clark County Water Reclamation District, GO,       
  Series B, 5.50%, 7/01/29    1,994  2,167,197 
        4,373,353 
New York - 1.0%         
Utilities - 1.0%  New York City Municipal Water Finance Authority, RB,     
  Series FF-2, 5.50%, 6/15/40    1,095  1,186,621 
Texas - 2.4%         
Utilities - 2.4%  City of San Antonio, Texas, Refunding RB,       
  Series A, 5.25%, 2/01/31    2,609  2,754,001 
  Total Municipal Bonds Transferred to       
  Tender Option Bond Trusts - 26.3%      29,941,177 
  Total Long-Term Investments (Cost - $175,983,524) - 158.8%    180,869,475 
  Short-Term Securities    Shares   
  FFI Institutional Tax-Exempt Fund, 0.23% (e)(f)    6,000,000  6,000,000 
  Total Short-Term Securities       
  (Cost - $6,000,000) - 5.3%      6,000,000 
  Total Investments (Cost - $181,983,524*) - 164.1%    186,869,475 
  Liabilities in Excess of Other Assets - (1.0)%      (1,146,571) 
  Liability for Trust Certificates, Including Interest     
  Expense and Fees Payable - (13.5)%      (15,318,148) 
  Preferred Shares, at Redemption Value - (49.6)%    (56,529,835) 
  Net Assets Applicable to Common Shares - 100.0%  $ 113,874,921 

* The cost and unrealized appreciation (depreciation) of investments as of October 31,

2009, as computed for federal income tax purposes, were as follows:

Aggregate cost  $ 167,926,317 
Gross unrealized appreciation  $ 7,122,345 
Gross unrealized depreciation  (3,485,124) 
Net unrealized appreciation  $ 3,637,221 

(a) Represents a zero-coupon bond. Rate shown reflects the current yield as of report date.

(b) US government securities, held in escrow, are used to pay interest on this security as well as to retire the bond in full at
the date indicated, typically at a premium to par.

(c) Security is collateralized by Municipal or US Treasury Obligations.

(d) Securities represent bonds transferred to a tender option bond trust in exchange for which the Fund acquired residual
interest certificates. These securities serve as collateral in a financing transaction.

(e) 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:

Affiliate  Net Activity  Income   
FFI Institutional Tax-Exempt Fund  $ 3,698,450  $ 4,705 

(f) Represents the current yield as of report date.

7

BlackRock MuniYield Insured Investment Fund (MFT)

Schedule of Investments October 31, 2009 (Unaudited)

• Fair Value Measurements - Various inputs are used in determining the fair value of investments, which are as follows:
• Level 1 - price quotations in active markets/exchanges for identical assets and liabilities

• Level 2 - other observable inputs (including, but not limited to: quoted prices for similar assets or liabilities in
markets that are active, quoted prices for identical or similar assets or liabilities in markets that are not active,
inputs other than quoted prices that are observable for the assets or liabilities (such as interest rates, yield curves,
volatilities, prepayment speeds, loss severities, credit risks and default rates) or other
market-corroborated inputs)

• Level 3 - unobservable inputs based on the best information available in the circumstances, to the extent observable
inputs are not available (including the Fund's own assumptions used in determining the fair value of investments)

The inputs or methodology used for valuing securities are not necessarily an indication of the risk associated with
investing in those securities. For information about the Fund's policy regarding valuation of investments and other
significant accounting policies, please refer to the Fund's most recent financial statements as contained in its annual
report.

The following table summarizes the inputs used as of October 31, 2009 in determining the fair valuation of the Fund's
investments:

  Investments in 
Valuation Inputs  Securities 
  Assets 
Level 1 - Short-Term Securities  $ 6,000,000 
Level 2 - Long-Term Investments1  180,869,475 
Level 3  - 
Total  $ 186,869,475 

1 See above Schedule of Investments for values in each sector.

8

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 13(a)-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 MuniYield Insured Investment Fund

By: /s/ Anne F. Ackerley
Anne F. Ackerley
Chief Executive Officer of
BlackRock MuniYield Insured Investment Fund

Date: December 18, 2009

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/ Anne F. Ackerley
Anne F. Ackerley
Chief Executive Officer (principal executive officer) of
BlackRock MuniYield Insured Investment Fund

Date: December 18, 2009

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

Date: December 18, 2009