Urine extravasation in the early postoperative period after renal transplantation is a serious complication requiring expedient surgical intervention. Whereas clinical and laboratory findings are inconclusive, radiologic diagnostic studies have definite value. Routine ultrasound and radioisotope studies were performed on 111 renal transplant patients. In the eight who developed urine extravasation, ultrasound and/or radioisotope studies identified the extravasation in seven cases. Four of the eight were studied by intravenous pyelography and another two were studied by cystography. All results were positive. We recommend use of radioisotope and ultrasound studies for routine postoperative screening with invasive techniques reserved for inconclusive cases.