This study was designed to compare the effectiveness of two approaches to urinary catheter management in controlling postoperative urinary dysfunction in 110 patients following abdominoperineal resection or low anterior bowel resection. Patients, stratified by sex and surgical procedure, were randomly assigned to either straight gravity drainage or a 6-day progressive catheter clamping program. The bladder training program following abdominoperineal resection reduced significantly the urinary dysfunction rate in women but not in men. Marked differences in dysfunction rates were related to type of surgery, gender, and surgeon. Etiology of postoperative voiding dysfunction in various groups is discussed.