Acute renal failure requiring renal replacement therapy can complicate cardiopulmonary bypass in children. Peritoneal dialysis has been shown to stabilize electrolytes and improve fluid status in these patients. To assess dialysis adequacy in this setting, we prospectively measured Kt/V and creatinine clearance in five patients (6-839 days of age) requiring renal replacement therapy at our institution. Median dialysis creatinine clearance was 74.25 L/week/1.73m(2) (range 28.28-96.63 L/week/1.73m(2)). Residual renal function provided additional solute clearance as total creatinine clearance was 215.97 L/week/1.73m(2) (range 108.04-323.25 L/week/1.73m(2)). Dialysis Kt/V of >2.1 (median 4.84 [range 2.12-5.59]) was achieved in all patients. No dialysis-associated complications were observed. We conclude that peritoneal dialysis is a safe, simple method of providing adequate clearance in children who develop acute renal failure following exposure to cardiopulmonary bypass.