<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM ATHERSYS,
INC AS OF AND FOR THE YEAR ENDED DECEMBER 31, 1999 (AUDITED) AND AS OF AND FOR
THE SIX MONTHS ENDED JUNE 30, 2000 (UNAUDITED) AND IS QUALIFIED IN ITS ENTIRETY
BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<CIK> 0001051521
<NAME> ATHERSYS, INC.
<MULTIPLIER> 1,000

                                                  
<PERIOD-TYPE>                   YEAR                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-1999             DEC-31-2000
<PERIOD-START>                             JAN-01-1999             JAN-01-2000
<PERIOD-END>                               DEC-31-1999             JUN-30-2000
<CASH>                                           3,270                  26,402
<SECURITIES>                                     6,006                  24,415
<RECEIVABLES>                                        0                       0
<ALLOWANCES>                                         0                       0
<INVENTORY>                                          0                       0
<CURRENT-ASSETS>                                 9,624                  43,785
<PP&E>                                           1,903                   2,945
<DEPRECIATION>                                   (403)                   (675)
<TOTAL-ASSETS>                                  12,190                  54,628
<CURRENT-LIABILITIES>                              879                   1,511
<BONDS>                                              0                       0
<PREFERRED-MANDATORY>                                0                       0
<PREFERRED>                                     24,319                  68,460
<COMMON>                                            66                      66
<OTHER-SE>                                    (15,248)                (18,506)
<TOTAL-LIABILITY-AND-EQUITY>                    12,190                  54,628
<SALES>                                              0                       0
<TOTAL-REVENUES>                                     0                       0
<CGS>                                                0                       0
<TOTAL-COSTS>                                    4,944                   4,885
<OTHER-EXPENSES>                                12,015                       0
<LOSS-PROVISION>                                     0                       0
<INTEREST-EXPENSE>                                  78                      34
<INCOME-PRETAX>                               (16,598)                 (4,072)
<INCOME-TAX>                                         0                       0
<INCOME-CONTINUING>                           (16,598)                 (4,072)
<DISCONTINUED>                                       0                       0
<EXTRAORDINARY>                                      0                       0
<CHANGES>                                            0                       0
<NET-INCOME>                                  (16,598)                 (4,072)
<EPS-BASIC>                                     (2.85)                  (0.75)
<EPS-DILUTED>                                   (2.85)                  (0.75)