Exhibit 11.1 Renal Treatment Centers, Inc. and Subsidiaries COMPUTATION OF NET INCOME PER COMMON SHARE AND NET INCOME PER COMMON SHARE--ASSUMING DILUTION for the three and six months ended June 30, 1997 and 1996 Three Months Ended Six Months Ended June 30, June 30, 1997 1996 1997 1996 - ------------------------------------------------------------------------------------------------------------------------------------ Reconciliation of numerator: Net income for use in computing net income per common share $ 4,606,089 $ 3,390,066 $ 8,569,205 $ 4,848,663 Add back interest on note, tax effected 34,122 62,708 34,122 130,373 ------------------------- ----------------------------- Adjusted net income for use in computing net income per common share--assuming dilution $ 4,640,211 $ 3,452,774 $ 8,603,327 $ 4,979,036 ========================= ============================= Reconciliation of denominator Weighted average number of shares outstanding for use in computing net income per common share 24,962,389 25,828,734 24,737,326 25,284,349 Weighted average shares assumed issued upon conversion of note 54,771 661,501 246,914 661,501 Dilutive effect of outstanding stock options 827,610 766,102 805,580 766,102 ------------------------- ----------------------------- Weighted average number of common shares and equivalents outstanding--assuming dilution 25,844,770 27,256,337 25,789,820 26,711,952 ========================= ============================= Net income per common share $ 0.18 $ 0.13 $ 0.35 $ 0.19 ========================= ============================= Net income per common share--assuming dilution $ 0.18 $ 0.13 $ 0.33 $ 0.19 ========================= =============================