SLM Corporation
Medium Term Notes, Series B

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With Maturities of 9 Months or More from Date of Issue

Registration No. 333-90316
Filed Pursuant to Rule 424(b)(3)
 Pricing Supplement No. 257
(To Prospectus dated January 23, 2003 and
Prospectus Supplement dated January 23, 2003)		   Trade Date: 4/26/04
 Issue Date: 4/29/04		    

The date of this Pricing Supplement is 4/26/04

 
    
    
    
    
  
Interest Payment
    
  
Subject to Redemption
    
    
    
CUSIP
   Stated Interest Rate Per Annum(1)
   Maturity Date
   Price to Public(2)(3)
   Discounts & Commissions
   Frequency
   First Payment
   Survivor's Option
   Yes/No
   Date and terms of redemption
   Aggregate Principal Amount
   Net Proceeds
   OID Status
78490FLT4   FLOAT   6/15/2009   100%   0.750%   Quarterly(4 ) 09/15/04   No   No       653,000   648,102.50   N

Floating Rate Index
 
Spread
 
Reset Period(4)
 
Accrual Method
 
Maximum Interest Rate
 
Minimum Interest Rate
 
 
91 Day T-Bill   0.500%   Weekly   Actual/Actual (Payment Basis)   N/A   N/A    




Effective April 7, 2003 the name of Salomon Smith Barney Inc., an agent of the program, was changed to Citigroup Global Markets Inc.

(1)
The interest rates on the Ed Notes may be changed by SLM Corporation from time to time, but any such change will not affect the interest rate on any Ed Notes offered prior to the effective date of the change.

(2)
Expressed as a percentage of aggregate principal amount.

(3)
See "Supplemental Plan of Distribution" in the Prospectus supplement for additional information concerning price to public and underwriting compensation.

(4)
On the Interest Reset Date, which is the day after the 3 month T Bill auction, the Calculation Agent will establish the new rate based on the BEY for the 3 month T Bill auction published in H.15 (http://www.publicdebt.treas.gov/of/ofrespr.htm).
 In the event that the results of the 91 day Treasury Bill auction ceases to be published or reported, or that no auction is held in a particular week, then the rate in effect as a result of the last such report will remain in effect until such time, as the results of auctions of 91 day Treasury Bills will again be published.