Background Laparoscopic dismembered pyeloplasty is technically feasible for ureteropelvic junction (UPJ) obstruction although it is still challenged by its technical difficulty and time-consuming. In this study, we compared the initial results of retroperitoneal laparoscopic pyeloplasty versus a combined laparoscopic dissection and open reconstruction through a small incision in the treatment of UPJ obstruction.Methods Sixty-four patients with primary UPJ obstruction underwent pyeloplasty: 32 patients underwent laparoscopic procedure and 32 patients underwent open assisted laparoscopic surgery including two steps, ie, laparoscopic dissection of the UPJ transperitoneally and then pyeloplasty via an extended small incision. The demographic data and intraoperative, postoperative and follow-up conditions of patients were compared between the two groups.Results Preoperative data were comparable in the patients of the two groups. The operative time was shorter (60.9 minutes vs 157.7 minutes, P <0.0001) and the complication rate was lower (9.4% vs 31.3%, P <0.05) in the open assisted group than in the laparoscopic group. The estimated blood loss (42.3 ml vs 47.8 ml), time to have normal diet (37.6 hours vs 33.8 hours), and hospital stay (6.7 days vs 6.2 days) were equivalent. The operative success rate was 97% for the open assisted group and 91% for the laparoscopic group.Conclusions The procedure of combined small incision with laparoscopy for UPJ obstruction is technically easy, and the results are promising. It can be used as an altative to conventional procedures.