<TABLE> <S> <C>

<PAGE>
 
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
UNAUDITED CONSOLIDATED FINANCIAL STATEMENTS OF MCLEODUSA INCORPORATED AND
SUBSIDIARIES FOR THE THREE AND NINE MONTHS ENDED SEPTEMBER 30, 1997 AND IS
QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000
       
<S>                             <C>                     <C>
<PERIOD-TYPE>                   3-MOS                   9-MOS
<FISCAL-YEAR-END>                          DEC-31-1997             DEC-31-1997
<PERIOD-START>                              JUL-1-1997              JAN-1-1997
<PERIOD-END>                               SEP-30-1997             SEP-30-1997
<CASH>                                         336,074                 336,074
<SECURITIES>                                    89,816                  89,816
<RECEIVABLES>                                  114,311                 114,311
<ALLOWANCES>                                     8,241                   8,241
<INVENTORY>                                      3,781                   3,781
<CURRENT-ASSETS>                               574,069                 574,069
<PP&E>                                         350,972                 350,972
<DEPRECIATION>                                  14,761                  14,761
<TOTAL-ASSETS>                               1,361,999               1,361,999
<CURRENT-LIABILITIES>                          141,209                 141,209
<BONDS>                                        607,247                 607,247
<PREFERRED-MANDATORY>                                0                       0
<PREFERRED>                                          0                       0
<COMMON>                                           614                     614
<OTHER-SE>                                     578,842                 578,842
<TOTAL-LIABILITY-AND-EQUITY>                 1,361,999               1,361,999
<SALES>                                         49,325                 131,595
<TOTAL-REVENUES>                                49,325                 131,595
<CGS>                                           31,917                  80,680
<TOTAL-COSTS>                                   31,917                  80,680
<OTHER-EXPENSES>                                36,763                  99,784
<LOSS-PROVISION>                                   719                   2,041
<INTEREST-EXPENSE>                              11,270                  20,756
<INCOME-PRETAX>                               (23,705)                (53,556)
<INCOME-TAX>                                         0                       0
<INCOME-CONTINUING>                           (23,705)                (53,556)
<DISCONTINUED>                                       0                       0
<EXTRAORDINARY>                                      0                       0
<CHANGES>                                            0                       0
<NET-INCOME>                                  (23,705)                (53,556)
<EPS-PRIMARY>                                   (0.45)                  (1.02)
<EPS-DILUTED>                                   (0.45)                  (1.02)
        

</TABLE>