<ARTICLE> 5 <CIK> 0000931755 <NAME> AEI INCOME & GROWTH FUND XXI LIMITED PARTNERSHIP <PERIOD-TYPE> 3-MOS <FISCAL-YEAR-END> DEC-31-1999 <PERIOD-END> MAR-31-1999 <CASH> 296,601 <SECURITIES> 0 <RECEIVABLES> 0 <ALLOWANCES> 0 <INVENTORY> 0 <CURRENT-ASSETS> 296,601 <PP&E> 18,793,585 <DEPRECIATION> (946,306) <TOTAL-ASSETS> 18,143,880 <CURRENT-LIABILITIES> 471,550 <BONDS> 0 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <COMMON> 0 <OTHER-SE> 17,672,330 <TOTAL-LIABILITY-AND-EQUITY> 18,143,880 <SALES> 0 <TOTAL-REVENUES> 485,350 <CGS> 0 <TOTAL-COSTS> 212,078 <OTHER-EXPENSES> 0 <LOSS-PROVISION> 0 <INTEREST-EXPENSE> 0 <INCOME-PRETAX> 273,272 <INCOME-TAX> 0 <INCOME-CONTINUING> 273,272 <DISCONTINUED> 0 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 273,272 <EPS-PRIMARY> 11.35 <EPS-DILUTED> 11.35