<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM ONESOURCE
INFORMATION SERVICES INC.'S PRO FORMA CONDENSED BALANCE SHEET (UNAUDITED) FOR
SEPTEMBER 30, 1999 AND PRO FORMA CONDENSED STATEMENT OF OPERATIONS (UNAUDITED)
FOR THE NINE MONTHS ENDED SEPTEMBER 30, 1999 AND IS QUALIFIED IN ITS ENTIRETY
BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000
<CURRENCY> U.S. DOLLARS

                             
<PERIOD-TYPE>                   9-MOS
<FISCAL-YEAR-END>                          DEC-31-1998
<PERIOD-START>                             JAN-01-1999
<PERIOD-END>                               SEP-30-1999
<EXCHANGE-RATE>                                      1
<CASH>                                          14,711
<SECURITIES>                                         0
<RECEIVABLES>                                    7,131
<ALLOWANCES>                                       357
<INVENTORY>                                         43
<CURRENT-ASSETS>                                27,425
<PP&E>                                           8,626
<DEPRECIATION>                                   5,551
<TOTAL-ASSETS>                                  41,115
<CURRENT-LIABILITIES>                           26,876
<BONDS>                                              0
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                           100
<OTHER-SE>                                      13,979
<TOTAL-LIABILITY-AND-EQUITY>                    41,115
<SALES>                                         29,225
<TOTAL-REVENUES>                                29,225
<CGS>                                           11,177
<TOTAL-COSTS>                                   11,177
<OTHER-EXPENSES>                                23,987
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                                 459
<INCOME-PRETAX>                                (4,898)
<INCOME-TAX>                                      (31)
<INCOME-CONTINUING>                            (4,867)
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                   (4,867)
<EPS-BASIC>                                     (0.58)
<EPS-DILUTED>                                   (0.58)