To evaluate endoscopic trigonoplasty compared to open trigonoplasty for vesicoureteral reflux, we analyzed clinical results, complications, the use of analgesics for postoperative pain and bladder irritability and postoperative length of hospitalization. One of six patients undergoing endoscopic trigonoplasty subsequently underwent open trigonoplasty due to failure of trocar placement, therefore, 7 patients having vesicoureteral refluxy renoureteral units underwent open trigonoplasty and 5 patients with vesicoureteral reflux 7 renoureteral units underwent endoscopic trigonoplasty. Mean operative time was 143 +/- 48 minutes for open surgery and 185 +/- 54 minutes for endoscopic surgery. Vesicoureteral reflux disappeared in 8 renoureteral units but was worse in one unit after open trigonoplasty, while vesicoureteral reflux subsided in 6 units and improved in one unit from grade II to grade I after endoscopic trigonoplasty. There were no intraoperative complications after open surgery, while one patient had pneumoperitoneum due to inadequate placement of a trocar during endoscopic surgery. There were no early postoperative complications after endoscopic surgery. However, 2 patients developed hematuria after open surgery. The degree of postoperative pain and irritability following endoscopic trigonoplasty was lower than that after open trigonoplasty and analgesics were used less frequently after endoscopic surgery. The mean postoperative hospital stay was 16.7 +/- 3.2 days for open surgery and 14.4 +/- 2.9 days for endoscopic surgery. These results indicate that endoscopic trigonoplasty is a useful procedure for vesicoureteral reflux because it is minimally invasive.