The records of 50 patients with acute renal failure secondary to bilateral ureteric obstruction were reviewed. An underlying malignant disorder was the cause of the obstruction in 38 of the patients and had not previously been diagnosed in almost half of them. Carcinomas of the cervix and prostate were the most frequent malignant disorders, and aggressive management resulted in good survival rates. Similarly, the outcome for patients with benign bilateral ureteric obstruction, usually caused by retroperitoneal fibrosis, was good with proper management.