Postoperative overdistention of the bladder should be avoided, but this does not justify leaving routine postoperative catheterization orders to the interpretation and discretion of the nursing service. If the attending physician, intern, or nurse gives adequate attention to the patient during the first few hours after an operation, the frequency of catheterizations can be greatly reduced. Responses to a questionnaire sent to 111 physicians of the American Urological Association indicated that catheterization is usually not considered necessary during the first six hours and thereafter is necessary only if the patient has not urinated voluntarily and has a full bladder. The attending physician should evaluate the need for catheterization and should, whenever possible, perform it himself. When catheterization is done without a break in the sterile technique and with caution to avoid tissue damage, complications are infrequent.