Cisplatin nephrotoxicity was evaluated by serial pretreatment and post-treatment 24-hour creatinine clearance determinations in 43 patients who received 295 monthly infusions of 60 mg/m2 of this drug. An aggressive standard hydration protocol was used without diuretic administration. Fourteen of these patients had a single kidney. Older patients and patients with a single kidney had lower pretreatment creatinine clearances when compared with younger persons with two functioning kidneys. Older and younger patients with two kidneys had an equal, progressive, dose-related deterioration of renal function. Renal function did not decline in persons with a single kidney but did so markedly in those with two kidneys. When administered at 60 mg/m2, cisplatin dose or schedule modification is not indicated on the basis of advancing age or decreased renal function secondary to the surgical loss or total ureteral obstruction of one kidney.