UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form N-CSR

CERTIFIED SHAREHOLDER REPORT OF REGISTERED

MANAGEMENT INVESTMENT COMPANIES

Investment Company Act File Number: 811- 21411

Eaton Vance Senior Floating-Rate Trust

(Exact Name of registrant as Specified in Charter)

The Eaton Vance Building, 255 State Street, Boston, Massachusetts 02109

(Address of Principal Executive Offices)

Alan R. Dynner

The Eaton Vance Building, 255 State Street, Boston, Massachusetts 02109

(Name and Address of Agent for Services)

(617) 482-8260

(Registrant’s Telephone Number)

October 31

Date of Fiscal Year End

April 30, 2006

Date of Reporting Period

Item 1. Reports to Stockholders

[[Insert Shareholder Report(s) Here]]

Eaton Vance Senior Floating-Rate Trust as of April 30, 2006

INVESTMENT UPDATE

The Trust

Performance for the Past Six Months

·                     Based on its April 2006 monthly dividend of $0.127 and a closing share price of $17.65, Eaton Vance Senior Floating-Rate Trust, a closed-end fund traded on the New York Stock Exchange (The “Trust”) had a market yield of 8.63%.(1)

·                     Based on share price (traded on the New York Stock Exchange), the Trust had a total return of 6.79% for the six months ended April 30, 2006. That return was the result of an increase in share price from $17.21 on October 31, 2005 to $17.65 on April 30, 2006 and the reinvestment of $0.720 in regular monthly dividends.

·                     Based on net asset value, the Trust had a total return of 4.80% for the six months ended April 30, 2006. That return was the result of an increase in net asset value per share from $18.74 on October 31, 2005 to $18.86 on April 30, 2006, and the reinvestment of all distributions.

·                     For performance comparison, the S&P/LSTA Leveraged Loan Index, had a return of 3.38% for the six months ended April 30, 2006.(2) The Lipper Loan Participation Funds Classification — the Fund’s peer group — had an average total return of 3.61% for the same period.(2)

The Trust’s Investments

·                     The Trust’s loan investments represented 429 borrowers and 38 industries as of April 30, 2006. The Trust’s average loan size was 0.20% of total assets, and no industry constituted more than 7.0% of the Trust’s total assets. Building and development (which includes companies that manage/own apartments, shopping malls and commercial office buildings, among others), health care, chemicals and plastics, leisure goods/activities/movies and automotive were the Trust’s largest industry weightings.

·                     The loan market was characterized by higher interest rates, narrowing credit spreads and a soaring volume of new issues. The London Inter-Bank Offered Rate (LIBOR) — the benchmark over which loan interest rates are typically set — rose in lockstep with the Federal Reserve’s Federal Funds rate, which benefited the Trust’s investors. However, although the average credit spread over LIBOR continued to decline due to strong investor demand, there were signs late in the period that the recent spread compression may have run its course. Investors were becoming resistant to new loans with lower spreads, with some loans being repriced in certain instances.

·                     The Trust also had a 9.5% position in high-yield bonds, which was additive to performance. The highyield bond segment remained focused on B-rated bonds and on shorter maturities, which provided more flexibility in times of increasing market volatility.

·                     The Trust’s share price traded at a discount versus its NAV, as have many fixed-income, closed-end funds that employ leverage. However, most of these funds buy fixed-rate investments and often use shorter and/or floating-rate borrowings, which, in a rising interest rate environment, can limit share price appreciation and impair a closed-end fund’s ability to earn and pay dividends. For this reason, closed-end bond funds may trade flat-to-lower in a rising-rate climate, such as the one we have recently experienced. In contrast, the Trust invests primarily in floating-rate instruments, which help limit declines in NAV and may add income in a rising-rate environment. While it is difficult to attribute the Trust’s market share discount to NAV to one factor, we believe a likely cause was a market perception that rising rates impair the net asset values of fixed-rate, closed-end bond funds. If this were the cause, we believe that the market failed to distinguish the floating-rate nature of most of the Trust’s assets. Although there is no certainty that the Trust will continue to do so, the Trust raised its dividend during the six-month period.

·                     At April 30, 2006, the Trust had leverage in the amount of approximately 39% of the Trust’s total assets. The Trust employs leverage though the issuance of Auction Preferred Shares (“APS”).(3) Use of financial leverage creates an opportunity for increased income but, at the same time, creates special risks (including the likelihood of greater volatility of net asset value and market price of common shares). The cost of the Trust’s APS rises and falls with changes in short-term interest rates. Such increases/decreases in the cost of the Trust’s APS may be offset by increased/decreased income from the Trust’s senior loan investments.

(1)          The Trust’s market yield is calculated by dividing the most recent dividend per share by the share market price at the end of the period and annualizing the result.

(2)          It is not possible to invest directly in an Index or Lipper Classification. The Index’s total return does not reflect the commissions or expenses that would have been incurred if an investor individually purchased or sold the securities represented in the Index.

(3)          Performance results reflect the effect of leverage resulting from the Trust’s Auction Preferred Shares. In the event of a rise in long-term interest rates, the value of the Trust’s investment portfolio could decline, which would reduce the asset coverage for its Auction Preferred Shares.

Past performance is no guarantee of future results. Returns are historical and are calculated by determining the percentage change in net asset value or share price (as applicable) with all distributions reinvested. Investment return and principal value will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Performance is for the stated time period only; due to market volatility, the Trust’s current performance may be lower or higher than the quoted return. For performance as of the most recent month end, please refer to www.eatonvance.com.

Shares of the Trust are not insured by the FDIC and are not deposits or other obligations of, or guaranteed by, any depository institution. Shares are subject to investment risks, including possible loss of principal invested.

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Eaton Vance Senior Floating-Rate Trust as of April 30, 2006

PERFORMANCE

Performance(1)

(1)          Performance results reflect the effect of leverage resulting from the Trust’s issuance of Auction Preferred Shares. In the event of a rise in long-term interest rates, the value of the Trust’s investment portfolio could decline, which would reduce the asset coverage for its Auction Preferred Shares.

Past performance is no guarantee of future results. Returns are historical and are calculated by determining the percentage change in net asset value or share price (as applicable) with all distributions reinvested. Investment return and principal value will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Performance is for the stated time period only; due to market volatility, the Trust’s current performance may be lower or higher than the quoted return. For performance as of the most recent month end, please refer to www.eatonvance.com.

Diversification by Industries(2)

By total investments

(2)             Reflects the Trust’s investments as of April 30, 2006. Industries are shown as a percentage of the Trust’s total loan and corporate bond and note investments. Portfolio information may not be representative of current or future investments and are subject to change due to active management.

Trust Allocations(3)

(3)             Trust Allocations are shown as a percentage of the Trust’s total investments as of April 30, 2006. Trust statistics may not be representative of the Trust’s current or furture investments and are subject to change due to active management.

The views expressed in this report are those of the portfolio managers and are current only through the end of the period of the report as stated on the cover. These views are subject to change at any time based upon market or other conditions, and Eaton Vance disclaims any responsibility to update such views. These views may not be relied on as investment advice and, because investment decisions for an Eaton Vance fund are based on many factors, may not be relied on as an indication of trading intent on behalf of any Eaton Vance fund. 3 Trust Allocations are shown as a percentage of the Trust’s total investments as of April 30, 2006.

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