Summary Five children with acute renal failure,ranging in age from 3 months to 11 years, were treated by intermittent peritoneal dialysis for periods ranging from 5 hours to 33 days. The indications for dialysis included oneor more of the following: oliguria, anuria, edema, hyperkalemia, azotemia, hypervolemia, cardiac failure, encephalopathy, and drug intoxication. The procedure proved a practical and effective means of substituting for the kidney and in one case was repeated 85 times during a 33 day period. Adjustment in body fluid volume andcomposition was accomplished by varying the electrolyte composition and osmolality of the dialysis fluid to meet the need at any given time. Large quantities of edema fluid, urea, and potassium were removed. The decrements in blood urea nitrogen were not particularly outstanding. Hypotonic dialyzing fluid used in a severely ill infant with tubular necrosis and cardiac failure resulted in acute pulmonary edema and illustrates the danger associated with the use of hypotonic dialyzing fluid. One patient developed peritonitis after 22 days of dialysis but responded promptly to therapy; it was not necessary to discontinue the procedure. The use of intermittent peritoneal dialysisin renal failure, as with other dialyzing procedures, should be reserved for potentially reversible cases.