The peritoneal clearance of inorganic sulfate was measured in 6 infants and 12 children with end-stage renal disease who were receiving continuous ambulatory peritoneal dialysis. Serum sulfate, which was elevated before dialysis, changed little during the 5-hour dialysis period. The dialysis sulfate concentration increased at the same rate as creatinine. Net clearance of the two metabolites was not different. It was calculated that the removal by continuous ambulatory peritoneal dialysis in 24 h is comparable to the daily excretion of SO<sub>4</sub> in healthy children.