Open dismembered pyeloplasty by a retroperitoneal approach remains the reference standard for correcting ureteropelvic junction (UPJ) obstruction in children. We prospectively compared the results of laparoscopic and open pyeloplasty in children with UPJ obstruction.During the period April 2003 to March 2005, 15 children underwent laparoscopic pyeloplasty and 14 children underwent open pyeloplasty. The two groups were similar in age and mean weight. We prospectively analyzed and compared operative time, postoperative pain and activity, complications, and hospital stay in the two groups. The mean follow-up was 23 and 24 months in the laparoscopy and open surgery group, respectively.The mean operative time was significantly shorter in the open surgery group (159 +/- 21.39 [SD] v 214 +/- 32.26 minutes; P = 5.874 x 10(-6)). Postoperative discomfort/pain on day 7 was significantly less in the laparoscopic group, and the mean hospital stay was significantly shorter (P = 0.018019).The benefits of laparoscopic pyeloplasty include a high reproducible success rate comparable to the results achieved by open pyeloplasty. Our results indicate minimal morbidity such as pain and a quick return to normal activities. The hospital stay is significantly reduced, although the operative times are long compared with open pyeloplasty.