Pricing Supplement No. 21 dated July 14, 2003
(to Prospectus dated November 18, 2002
and Prospectus Supplement dated November 18, 2002)		   Filed under Rule 424(b)(3)
File No. 333-90316

SLM Corporation
Medium Term Notes, Series A
Due 9 Months or Longer From the Date of Issue

Principal Amount: $750,000,000   Floating Rate Notes: o   Fixed Rate Notes: ý

Original Issue Date:
July 21, 2003
 
Closing Date:    July 21, 2003
 
CUSIP Number:
78442F AZ1

Maturity Date:
August 1, 2033
 
Option to Extend Maturity:
ý    No
 
Specified Currency:
U.S. Dollars

 
 
 
If Yes, Final Maturity Date:
o    Yes
 
 
 
Redeemable at the option of the Company:   ý    No   Redemption Price:   Not Applicable.
    o    Yes   Redemption Dates:   Not Applicable.
Repayment at the option of the Holder::   ý    No   Repayment Price:   Not Applicable.
    o    Yes   Repayment Dates:   Not Applicable.

Applicable to Fixed Rate Notes Only:

Interest Rate:    5.625%
 
Interest Payment Dates:
Each February 1st and August 1st during the term of the Notes, beginning February 1, 2004, subject to adjustment in accordance with the following business day convention.

Interest Accrual Method:    30/360
 
Interest Periods:
From and including the Closing Date, or the previous February 1st or August 1st, as the case may be, to and including the next succeeding January 31st or July 31st, as the case may be, with no adjustment to period end dates for accrual purposes.
Citigroup   Morgan Stanley

Joint Book-Running Managers
ABN AMRO Incorporated
Banc One Capital Markets, Inc.
JPMorgan
Merrill Lynch & Co.		   Banc of America Securities LLC
Credit Suisse First Boston
Lehman Brothers
UBS Warburg

Co-Managers

July 14, 2003

MTN 0042

Form: Book-entry.    

Denominations:
$1,000 minimum and integral multiples of $1,000 in excess thereof.

Trustee:
JPMorgan Chase Bank, formerly known as The Chase Manhattan Bank.

Agents:
The following agents are acting as underwriters in connection with this issuance.

 
Agents
 
Principal Amount of Notes
  Morgan Stanley & Co. Incorporated   $ 300,000,000
  Citigroup Global Markets Inc.     300,000,000
  ABN AMRO Incorporated     18,750,000
  Banc of America Securities LLC     18,750,000
  Banc One Capital Markets, Inc.     18,750,000
  Credit Suisse First Boston LLC     18,750,000
  J.P. Morgan Securities Inc.     18,750,000
  Lehman Brothers Inc.     18,750,000
  Merrill Lynch, Pierce, Fenner & Smith Incorporated     18,750,000
  UBS Warburg LLC     18,750,000
     
      Total   $ 750,000,000

Issue Price:
99.025%.

Agents' Commission:
0.750%.

Net Proceeds:
$737,062,500.

Concession:
0.450%.

Reallowance:
0.250%.

CUSIP Number:
78442F AZ1

ISIN Number:
US78442F AZ18

Obligations of SLM Corporation and any subsidiary of SLM Corporation are not guaranteed
by the full faith and credit of the United States of America. Neither SLM Corporation nor any
subsidiary of SLM Corporation (other than Student Loan Marketing Association) is a
government-sponsored enterprise or an instrumentality
of the United States of America.

MTN 0042