During the 6-year period ending in 1988, suture entrapment and secondary postoperative ureteral obstruction occurred in 18 (0.33%) of the 5379 patients who underwent major pelvic operations for benign conditions. Sixteen cases occurred after vaginal surgery and two after abdominal hysterectomy. Placement of the McCall suture or sutures for elevation of a bladder neck caused ureteral entrapment most frequently. Early diagnosis was facilitated by comparison of preoperative and postoperative serum creatinine levels. The mean change in serum creatinine level in patients with unilateral obstruction was an increase of 0.8 mg/dl. Treatment by either antegrade placement of ureteral stents or abdominal exploration with deligation or ureteroneocystotomy was successful in all cases. Retrograde placement of ureteral stents was unsuccessful.