<Page> Exhibit 12.1 THE PEOPLES GAS LIGHT AND COKE COMPANY AND SUBSIDIARY COMPANIES STATEMENT RE: COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES (Dollars in Thousands) <Table> <Caption> FISCAL YEARS ENDED SEPTEMBER 30, 6 months ended 12 months ended ------------------------------------------------------- 3/31/2003 3/31/2003 2002 2001 2000 1999 1998 -------------- --------------- --------- ----------- --------- --------- --------- Net Income Before Preferred Stock Dividends $ 77,991 $ 78,513 $ 77,818 $ 75,259 $ 73,576 $ 78,217 $ 68,378 Add - Income Taxes 47,088 46,913 47,832 47,692 41,954 44,115 38,188 Fixed Charges excluding capitalized interest 11,804 22,430 23,673 36,737 33,640 31,398 33,141 ----------- ------------ --------- ----------- --------- --------- --------- Earnings $ 136,883 $ 147,856 $ 149,323 $ 159,688 $149,170 $ 153,730 $ 139,707 ----------- ------------ --------- ----------- --------- --------- --------- Fixed Charges including capitalized interest $ 11,804 $ 22,430 $ 23,673 $ 36,737 $ 34,462 $ 34,040 $ 33,786 Ratio of Earnings to Fixed Charges 11.60 6.59 6.31 4.35 4.33 4.52 4.14 ----------- ------------ --------- ----------- --------- --------- --------- </Table>