c55397_nq.htm -- 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 811-21181

Name of Fund: BlackRock Municipal 2020 Term Trust (BKK)

Fund Address: 100 Bellevue Parkway, Wilmington, DE 19809

Name and address of agent for service: Donald C. Burke, Chief Executive Officer, BlackRock Municipal 2020 Term Trust, 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: 12/31/2008

Date of reporting period: 07/01/2008 – 09/30/2008


Item 1 – Schedule of Investments

BlackRock Municipal 2020 Term Trust  
Schedule of Investments September 30, 2008 (Unaudited) (Percentages shown are based on Net Assets)
      Par        
State   Municipal Bonds (000)     Value  
Alabama - 0.4%   Courtland, Alabama, IDB, Solid Waste Disposal Revenue Refunding          
    Bonds (International Paper Company Project),          
    Series A, 4.75%, 5/01/17 $  1,165     $  1,014,960  
Arizona - 0.8%   Salt Verde Financial Corporation, Arizona, Senior Gas Revenue Bonds,          
    5%, 12/01/18 1,500     1,237,065  
    Salt Verde Financial Corporation, Arizona, Senior Gas Revenue Bonds,          
    5.25%, 12/01/20 1,000     808,170  
            2,045,235  
California - 22.8%   California State Various Purpose, GO, 5%, 11/01/22 12,000     11,622,120  
    California Statewide Communities Development Authority Revenue          
    Bonds (John Muir Health), Series A, 5%, 8/15/22 5,000     4,689,950  
    Foothill/Eastern Corridor Agency, California, Toll Road Revenue          
    Refunding Bonds, CABS, 5.953%, 1/15/21 (a) 12,500     5,580,375  
    Foothill/Eastern Corridor Agency, California, Toll Road Revenue          
    Refunding Bonds, CABS, 5.844%, 1/15/22 (a) 10,000     4,138,000  
    Golden State Tobacco Securitization Corporation of California, Tobacco          
    Settlement Revenue Bonds, Series A-1, 6.625%, 6/01/13 (b) 3,000     3,340,290  
    Golden State Tobacco Securitization Corporation of California, Tobacco          
    Settlement Revenue Bonds, Series A-1, 6.75%, 6/01/13 (b) 12,010     13,435,707  
    Golden State Tobacco Securitization Corporation of California, Tobacco          
    Settlement Revenue Bonds, Series A-3, 7.875%, 6/01/13 (b) 975     1,134,617  
    Golden State Tobacco Securitization Corporation of California, Tobacco          
    Settlement Revenue Bonds, Series A-5, 7.875%, 6/01/13 (b) 1,470     1,710,654  
    Golden State Tobacco Securitization Corporation of California, Tobacco          
    Settlement Revenue Bonds, Series B, 5.375%, 6/01/10 (b) 10,000     10,362,900  
    Riverside County, California, Asset Leasing Corporation, Leasehold          
    Revenue Bonds (Riverside County Hospital Project),          
    5.69%, 6/01/25 (a)(c) 6,865     2,529,547  
            58,544,160  
Colorado - 1.8%   E-470 Public Highway Authority, Colorado Revenue Bonds, CABS, Senior          
    Series B, 5.36%, 9/01/22 (a)(c) 4,500     1,874,880  
    Park Creek Metropolitan District, Colorado, Senior Limited Tax          
    Supported Revenue Refunding Bonds, 5.25%, 12/01/25 3,000     2,626,410  
            4,501,290  
District of Columbia -   District of Columbia, Revenue Refunding Bonds (Friendship Public          
5.1%   Charter School, Inc.), 5.75%, 6/01/18 (d) 2,680     2,535,253  
    District of Columbia, Revenue Refunding Bonds (Friendship Public          
    Charter School, Inc.), 5%, 6/01/23 (d) 3,320     2,722,134  
Portfolio Abbreviations
  To simplify the listings of the portfolio holdings in the Schedule of Investments, the names of many of the securities have been abbreviated according to the list below.
  AMT   Alternative Minimum Tax (subject to)   IDA   Industrial Development Authority
  CABS   Capital Appreciation Bonds   IDB   Industrial Development Board
  COP   Certificates of Participation   M/F   Multi-Family
  EDA   Economic Development Authority   PCR   Pollution Control Revenue Bonds
  EDR   Economic Development Revenue Bonds   S/F   Single-Family
  GO   General Obligation Bonds   VRDN   Variable Rate Demand Notes

1

BlackRock Municipal 2020 Term Trust  
Schedule of Investments September 30, 2008 (Unaudited) (Percentages shown are based on Net Assets)
      Par        
State   Municipal Bonds (000)     Value  
    District of Columbia Tobacco Settlement Financing Corporation,          
    Asset-Backed Revenue Refunding Bonds, 6.50%, 5/15/33 $  4,215     $   3,765,765  
    Metropolitan Washington Airports Authority, D.C., Airport System          
    Revenue Refunding Bonds, AMT, Series C-2, 5%, 10/01/24 (e) 5,000     4,203,600  
            13,226,752  
Florida - 14.2%   Bellalago, Florida, Educational Facilities Benefits District, Capital          
    Improvement Special Assessment Bonds, Series A, 5.85%, 5/01/22 4,315     4,064,169  
    Broward County, Florida, School Board, COP, Series A,          
    5.25%, 7/01/22 (e) 1,250     1,215,900  
    Grand Hampton Community Development District, Florida, Capital          
    Improvement Special Assessment Bonds, 6.10%, 5/01/24 4,025     3,702,155  
    Habitat, Florida, Community Development, Special Assessment Bonds,          
    5.80%, 5/01/25 3,780     3,255,752  
    Jacksonville, Florida, Sales Tax Revenue Bonds, 5%, 10/01/22 5,160     4,950,710  
    Miami Beach, Florida, Health Facilities Authority, Hospital Revenue          
    Refunding Bonds (Mount Sinai Medical Center of Florida),          
    6.75%, 11/15/21 4,715     4,405,602  
    Middle Village Community Development District, Florida, Special          
    Assessment Bonds, Series A, 5.80%, 5/01/22 4,155     3,722,132  
    Pine Island Community Development District, Florida, Utilities System          
    Revenue Bonds, 5.30%, 11/01/10 495     476,586  
    Stevens Plantation Community Development District, Florida, Special          
    Assessment Revenue Bonds, Series B, 6.375%, 5/01/13 3,605     3,331,489  
    Village Community Development District Number 5, Florida, Special          
    Assessment Bonds, Series A, 6%, 5/01/22 2,845     2,793,079  
    Westchester Community Development District Number 1, Florida,          
    Special Assessment Bonds (Community Infrastructure), 6%, 5/01/23 5,375     4,603,096  
            36,520,670  
Georgia - 0.7%   Richmond County, Georgia, Development Authority, Environmental          
    Improvement Revenue Bonds (International Paper Co. Projects), AMT,          
    Series A, 5.75%, 11/01/27 2,350     1,907,448  
Illinois - 12.7%   Centerpoint Intermodal Center Program Trust, Illinois, Tax Allocation          
    Bonds, Class A, 8%, 6/15/23 (f) 2,155     1,947,991  
    Chicago, Illinois, O'Hare International Airport, General Airport Revenue          
    Bonds, Third Lien, Series A, 5%, 1/01/21 (g) 5,000     4,787,450  
    Chicago, Illinois, O'Hare International Airport, General Airport Revenue          
    Bonds, Third Lien, Series A, 5%, 1/01/22 (g) 7,000     6,603,870  
    Illinois Development Finance Authority Revenue Bonds (Depaul          
    University), Series C, 5.25%, 10/01/24 5,000     4,745,700  
    Illinois Educational Facilities Authority Revenue Bonds (Northwestern          
    University), 5%, 12/01/21 4,800     4,738,656  
    Illinois State Finance Authority, Student Housing Revenue Bonds (MJH          
    Education Assistance IV LLC), Senior Series A, 5.50%, 6/01/19 3,250     2,179,547  
    Illinois State Finance Authority, Student Housing Revenue Bonds (MJH          
    Education Assistance IV LLC), Sub-Series B, 5%, 6/01/24 1,075     310,675  

2

BlackRock Municipal 2020 Term Trust  
Schedule of Investments September 30, 2008 (Unaudited) (Percentages shown are based on Net Assets)
      Par        
State   Municipal Bonds (000)     Value  
    Lake, Cook, Kane and McHenry Counties, Illinois, Community Unit School          
    District Number 220, GO, Refunding, 5.25%, 12/01/20 (e)  $  1,000     $   1,030,250  
    Metropolitan Pier and Exposition Authority, Illinois, Dedicated State          
    Tax Revenue Refunding Bonds (McCormick), Series A,          
    5.26%, 6/15/22 (a)(c) 13,455     6,227,108  
            32,571,247  
Indiana - 5.9%   Indianapolis, Indiana, Airport Authority, Special Facilities, Revenue          
    Refunding Bonds (Federal Express Corporation Project),          
    AMT, 5.10%, 1/15/17 10,000     9,028,500  
    Lawrence, Indiana, M/F Housing, Revenue Refunding Bonds (Pinnacle          
    Apartments Project), AMT, 5.40%, 6/01/24 (h) 2,000     1,959,940  
    Vincennes, Indiana, EDR, Refunding, 6.25%, 1/01/24 4,805     4,115,723  
            15,104,163  
Kansas - 1.3%   Unified Government of Wyandotte County and Kansas City, Kansas, Sales          
    Tax Special Obligation Revenue Bonds (Kansas International Speedway          
    Corporation Project), 5.20%, 12/01/20 (a)(c) 6,440     3,383,254  
Kentucky - 0.7%   Kentucky Housing Corporation, Housing Revenue Bonds, AMT, Series C,          
    4.625%, 7/01/22 2,000     1,714,480  
Louisiana - 0.6%   De Soto Parish, Louisiana, Environmental Improvement Revenue          
    Bonds (International Paper Co. Project), AMT, Series A,          
    5.85%, 11/01/27 2,000     1,643,280  
Maryland - 5.9%   Frederick County, Maryland, Special Obligation Tax Bonds (Urbana          
    Community Development Authority), 6.625%, 7/01/25 3,000     2,910,300  
    Frederick County, Maryland, Special Obligation Tax Bonds (Urbana          
    Community Development Authority), Series A, 5.80%, 7/01/20 4,711     4,423,911  
    Maryland State Health and Higher Educational Facilities Authority,          
    Revenue Refunding Bonds (MedStar Health, Inc.), 5.375%, 8/15/24 8,500     7,910,950  
            15,245,161  
Massachusetts - 1.6%   Massachusetts State Development Finance Agency, Solid Waste Disposal          
    Revenue Bonds (Waste Management, Inc. Project),          
    AMT, 5.45%, 6/01/14 4,500     4,199,625  
Michigan - 0.5%   Michigan State Hospital Finance Authority, Hospital Revenue Refunding          
    Bonds (Sparrow Obligated Group), 4.50%, 11/15/26 1,500     1,223,190  
Minnesota - 0.5%   Minnesota State Higher Education Facilities Authority Revenue Bonds          
    (University of St. Thomas), Series Five Y, 5%, 10/01/24 1,250     1,165,150  
Mississippi - 1.0%   Warren County, Mississippi, Environmental Improvement Revenue          
    Bonds (International Paper Company Project), AMT, Series A,          
    5.85%, 11/01/27 3,000     2,464,920  
Missouri - 3.8%   Missouri State Development Finance Board, Infrastructure Facilities          
    Revenue Bonds (Branson Landing Project), Series A, 5.50%, 12/01/24 5,000     4,494,500  
    Missouri State Health and Educational Facilities Authority Health          
    Facilities Revenue Refunding Bonds (BJC Health System),          
    Series A, 5%, 5/15/20 5,500     5,285,390  
            9,779,890  
Nevada - 2.4%   Clark County, Nevada, EDR, Refunding (Alexander Dawson School of          
    Nevada Project), 5%, 5/15/20 5,000     4,756,550  

3

BlackRock Municipal 2020 Term Trust  
Schedule of Investments September 30, 2008 (Unaudited) (Percentages shown are based on Net Assets)
      Par        
State   Municipal Bonds (000)     Value  
    Henderson, Nevada, Local Improvement Districts, Special Assessment,          
    Series NO T-18, 5.15%, 9/01/21 $  1,765     $   1,292,615  
            6,049,165  
New Hampshire - 5.2%   New Hampshire Health and Education Facilities Authority, Revenue          
    Refunding Bonds (Elliot Hospital), Series B, 5.60%, 10/01/22 5,000     4,835,300  
    New Hampshire State Business Finance Authority, PCR, Refunding (Public          
    Service Company Project), AMT, Series B, 4.75%, 5/01/21 (c) 10,000     8,570,200  
            13,405,500  
New Jersey - 12.1%   Middlesex County, New Jersey, Improvement Authority Revenue          
    Bonds (George Street Student Housing Project), Series A,          
    5%, 8/15/23 1,000     891,570  
    New Jersey EDA, Cigarette Tax Revenue Bonds, 5.50%, 6/15/24 10,000     8,703,500  
    New Jersey EDA, EDR (Kapkowski Road Landfill Reclamation          
    Improvement District Project), AMT, Series B, 6.50%, 4/01/31 7,500     6,952,200  
    New Jersey EDA, First Mortgage Revenue Refunding Bonds          
    (The Winchester Gardens at Ward Homestead Project), Series A,          
    4.80%, 11/01/13 1,000     971,720  
    New Jersey EDA, Special Facility Revenue Bonds (Continental Airlines          
    Inc. Project), AMT, 7%, 11/15/30 5,000     4,112,100  
    New Jersey EDA, Special Facility Revenue Bonds (Continental Airlines          
    Inc. Project), AMT, 9%, 6/01/33 1,500     1,500,405  
    New Jersey Health Care Facilities Financing Authority, Revenue          
    Refunding Bonds (AtlantiCare Regional Medical Center), 5%, 7/01/20 2,110     1,997,516  
    New Jersey Health Care Facilities Financing Authority, Revenue          
    Refunding Bonds (Capital Health System Inc.), Series A,          
    5.75%, 7/01/23 4,000     3,830,920  
    New Jersey State Housing and Mortgage Finance Agency, S/F Housing          
    Revenue Bonds, AMT, Series T, 4.55%, 10/01/22 2,500     2,132,275  
            31,092,206  
New York - 8.2%   New York City, New York, City IDA, Special Facility Revenue Bonds          
    (American Airlines, Inc. - JFK International Airport),          
    AMT, 7.625%, 8/01/25 5,635     4,758,983  
    New York City, New York, City IDA, Special Facility Revenue Bonds          
    (Continental Airlines Inc. Project), AMT, 7.75%, 8/01/31 5,000     4,164,550  
    New York State Energy Research and Development Authority, Gas          
    Facilities Revenue Refunding Bonds (Brooklyn Union Gas          
    Company/Keyspan), AMT, Series A, 4.70%, 2/01/24 (i) 8,500     7,109,485  
    Tobacco Settlement Financing Corporation of New York Revenue Bonds,          
    Series B-1C, 5.50%, 6/01/20 5,000     5,059,000  
            21,092,018  
Ohio - 7.5%   American Municipal Power, Inc., Ohio, Revenue Refunding Bonds (Prairie          
    State Energy Campus Project), Series A, 5.25%, 2/15/23 5,000     4,833,200  
    Cuyahoga County, Ohio, Revenue Refunding Bonds,          
    Series A, 6%, 1/01/19 3,000     3,156,900  
    Cuyahoga County, Ohio, Revenue Refunding Bonds,          
    Series A, 6%, 1/01/20 10,000     10,431,500  

4

BlackRock Municipal 2020 Term Trust  
Schedule of Investments September 30, 2008 (Unaudited) (Percentages shown are based on Net Assets)
      Par        
State   Municipal Bonds (000)     Value  
    Pinnacle Community Infrastructure Financing Authority, Ohio, Revenue          
    Bonds, Series A, 6%, 12/01/22 $  1,060     $     958,516  
            19,380,116  
Oklahoma - 1.2%   Tulsa, Oklahoma, Municipal Airport Trust, Revenue Refunding Bonds,          
    Series A, 7.75%, 6/01/35 3,350     3,140,893  
Pennsylvania - 6.0%   Lancaster County, Pennsylvania, Hospital Authority Revenue Bonds          
    (Lancaster General Hospital Project), 5.75%, 9/15/13 (b) 7,500     8,232,225  
    Montgomery County, Pennsylvania, IDA, Revenue Bonds (Whitemarsh          
    Continuing Care Project), 6%, 2/01/21 1,275     1,128,286  
    Pennsylvania State Higher Educational Facilities Authority Revenue          
    Bonds (LaSalle University), 5.50%, 5/01/26 6,680     6,024,358  
    Philadelphia, Pennsylvania, Water and Wastewater Revenue Refunding          
    Bonds, VRDN, 8.10%, 6/15/23 (e)(j)(k) 90     90,000  
            15,474,869  
Tennessee - 3.2%   Tennessee Energy Acquisition Corporation, Gas Revenue Bonds,          
    Series A, 5.25%, 9/01/20 10,000     8,137,400  
Texas - 7.4%   Brazos River Authority, Texas, PCR, Refunding (TXU Energy Company LLC          
    Project), AMT, Series A, 6.75%, 4/01/38 1,100     1,026,872  
    North Texas Tollway Authority, System Revenue Refunding Bonds, First          
    Tier, Series A, 6%, 1/01/24 2,000     1,976,200  
    Port Corpus Christi, Texas, Industrial Development Corporation Revenue          
    Refunding Bonds, Series C, 5.40%, 4/01/18 3,500     3,305,995  
    Texas State Turnpike Authority, Central Texas Turnpike System First Tier          
    Revenue Bonds, CABS, Series A, 5.37%, 8/15/21 (a)(g) 7,990     3,599,655  
    Texas State Turnpike Authority, Central Texas Turnpike System First Tier          
    Revenue Bonds, CABS, Series A, 5.51%, 8/15/24 (a)(g) 8,450     3,037,437  
    Weatherford, Texas, Independent School District, GO, Refunding, CABS,          
    6.876%, 2/15/11 (a)(b) 4,040     1,772,025  
    Weatherford, Texas, Independent School District, GO, Refunding, CABS,          
    6.906%, 2/15/11 (a)(b) 4,040     1,876,661  
    Weatherford, Texas, Independent School District, GO, Refunding, CABS,          
    6.876%, 2/15/23 (a) 2,905     1,228,089  
    Weatherford, Texas, Independent School District, GO, Refunding, CABS,          
    6.906%, 2/15/24 (a) 2,905     1,148,085  
            18,971,019  
Virginia - 8.3%   Celebrate North Community Development Authority, Virginia, Special          
    Assessment Revenue Bonds, Series B, 6.60%, 3/01/25 5,000     4,632,800  
    Charles City County, Virginia, EDA, Solid Waste Disposal Revenue Bonds          
    (Waste Management, Inc.), AMT, 5.125%, 8/01/27 10,000     9,253,500  
    Mecklenburg County, Virginia, IDA, Exempt Facility Revenue Refunding          
    Bonds (UAE LP Project), 6.50%, 10/15/17 7,500     7,573,725  
            21,460,025  
Washington - 3.2%   Washington State Compound Interest Bonds, GO, Series S-5,          
    5.02%, 1/01/19 (a)(i) 10,000     5,907,700  
    Washington State, GO, CABS, Series F, 5.33%, 12/01/21 (a)(c) 4,630     2,260,181  
            8,167,881  

5

BlackRock Municipal 2020 Term Trust  
Schedule of Investments September 30, 2008 (Unaudited) (Percentages shown are based on Net Assets)
      Par        
State   Municipal Bonds (000)     Value  
Wisconsin - 2.2%   Wisconsin State Health and Educational Facilities Authority, Revenue          
    Refunding Bonds (Wheaton Franciscan Services, Inc.),          
    Series A, 5.50%, 8/15/17 $  2,880     $   2,709,648  
    Wisconsin State Health and Educational Facilities Authority, Revenue          
    Refunding Bonds (Wheaton Franciscan Services, Inc.),          
    Series A, 5.50%, 8/15/18 3,190     2,955,088  
            5,664,736  
Multi-State - 8.3%   Charter Mac Equity Issuer Trust, 5.75%, 4/30/15 (f)(l) 1,000     1,027,770  
    Charter Mac Equity Issuer Trust, 6%, 4/30/15 (f)(l) 4,000     4,149,480  
    Charter Mac Equity Issuer Trust, 6%, 4/30/19 (f)(l) 2,500     2,512,450  
    Charter Mac Equity Issuer Trust, 6.30%, 4/30/19 (f)(l) 2,500     2,565,100  
    MuniMae TE Bond Subsidiary LLC, 5.40% (f)(l)(m) 5,000     4,783,850  
    MuniMae TE Bond Subsidiary LLC, 5.80% (f)(l)(m) 5,000     4,524,450  
    MuniMae TE Bond Subsidiary LLC, Series D, 5.90%, (f)(l)(m) 2,000     1,784,820  
            21,347,920  
Puerto Rico - 5.8%   Puerto Rico Commonwealth, Public Improvement, GO,          
    Series B, 5.25%, 7/01/17 3,300     3,259,905  
    Puerto Rico Electric Power Authority, Power Revenue Bonds, Series NN,          
    5.125%, 7/01/13 (b) 10,900     11,757,939  
            15,017,844  
U.S. Virgin Islands -   Virgin Islands Public Finance Authority, Senior Lien Revenue Bonds          
0.4%   (Matching Fund Loan Note), Series A, 5.25%, 10/01/17 1,000     980,700  
    Total Municipal Bonds - 161.7%       415,637,167  
    Corporate Bonds          
    San Manuel Entertainment Authority Series 04-C,          
    4.50%, 12/01/16 (f) 4,000     3,670,320  
    Total Corporate Bonds - 1.4%       3,670,320  
    Municipal Bonds Transferred to          
    Tender Option Bond Trusts (n)          
Illinois - 1.9%   Chicago, Illinois, Water Revenue Refunding Bonds,          
    Second Lien, 5%, 11/01/20 (e) 5,000     4,957,300  
    Total Municipal Bonds Transferred to Tender Option          
    Bond Trusts - 1.9%       4,957,300  
    Total Long-Term Investments (Cost - $455,268,054) - 165.0%       424,264,787  
    Short-Term Securities Shares        
    Merrill Lynch Institutional Tax-Exempt Fund, 5.29% (o)(p) 5,400,000     5,400,000  
    Total Short-Term Securities          
    (Cost - $5,400,000) - 2.1%       5,400,000  
    Total Investments (Cost - $460,668,054*) - 167.1%       429,664,787  
    Other Assets Less Liabilities - 2.1%       5,341,887  
    Liability for Trust Certificates, Including Interest Expense          
    and Fees Payable - (1.5)%       (3,780,072 )
    Preferred Shares, at Redemption Value - (67.7)%       (174,124,694 )
    Net Assets Applicable to Common Shares - 100.0%       $ 257,101,908  

6

BlackRock Municipal 2020 Term Trust  
Schedule of Investments September 30, 2008 (Unaudited)            
*   The cost and unrealized appreciation (depreciation) of investments as of September 30, 2008, as computed for federal income tax purposes, were as follows:
 
  Aggregate cost $ 456,305,110    
  Gross unrealized appreciation $ 5,978,714    
  Gross unrealized depreciation   (36,369,037 )  
  Net unrealized depreciation $ (30,390,323 )  

(a)   Represents a zero-coupon bond. Rate shown reflects the effective yield at the time of purchase.
(b)   U.S. 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)   MBIA Insured.
(d)   ACA Insured.
(e)   FSA Insured.
(f)   Security exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be resold in transactions exempt from registration to qualified institutional investors.
(g)   AMBAC Insured.
(h)   FNMA Collateralized.
(i)   FGIC Insured.
(j)   Variable rate security. Rate shown is as of report date. Maturity shown is the final maturity date.
(k)   Security may have a maturity of more than one year at the time of issuance, but has variable rate and demand features that qualify it as a short-term security.
(l)   Security represents a beneficial interest in a trust. The collateral deposited into the trust is federally tax-exempt revenue bonds issued by various state or local governments, or their respective agencies or authorities. The security is subject to remarketing prior to its stated maturity, and is subject to mandatory redemption at maturity.
(m)   Security is a perpetual in nature and has no stated maturity date.
(n)   Securities represent bonds transferred to a tender option bond trust in exchange for which the Trust acquired residual interest certificates. These securities serve as collateral in a financing transaction.
(o)   Represents the current yield as of report date.
(p)   Investments in companies considered to be an affiliate of the Trust, for purposes of Section 2(a)(3) of the Investment Company Act of 1940, were as follows:
    Net      
  Affiliate Activity   Income  
  Merrill Lynch Institutional        
  Tax-Exempt Fund 5,400,000   $18,340  

7

BlackRock Municipal 2020 Term Trust  
Schedule of Investments September 30, 2008 (Unaudited)            
•   Effective January 1, 2008, the Trust adopted Financial Accounting Standards Board Statement of Financial Accounting Standards No. 157, "Fair Value Measurements" ("FAS 157"). FAS 157 clarifies the definition of fair value, establishes a framework for measuring fair values and requires additional disclosures about the use of 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 securities
         
    •   Level 2 - other observable inputs (including, but not limited to: quoted prices for 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 circumstance, to the extent observable inputs are not available (including the Trust's own assumption 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 Trust's policy regarding valuation of investments and other significant accounting policies, please refer to the Trust's most recent financial statements as contained in its semi-annual report.
 
  The following table summarizes the inputs used as of September 30, 2008 in determining the fair valuation of the Trust's investments:
  Valuation     Investments in  
  Inputs     Securities  
  Level 1   $ 5,400,000  
  Level 2     424,264,787  
  Level 3     -  
  Total   $ 429,664,787  

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 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 Municipal 2020 Term Trust
       
    By:
/s/ Donald C. Burke
      Donald C. Burke
      Chief Executive Officer of
      BlackRock Municipal 2020 Term Trust
       
    Date: November 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 Municipal 2020 Term Trust
       
    Date: November 24, 2008
       
    By:
/s/ Neal J. Andrews
      Neal J. Andrews
      Chief Financial Officer (principal financial officer) of
      BlackRock Municipal 2020 Term Trust
       
    Date: November 24, 2008