Percutaneous endopyelotomy was performed in 16 patients with ureteropelvic junction obstruction. The procedure was always completed with no intra-operative complication. After a mean follow-up of 18 months (6-30 mos), we report 12 good results (75%), 2 patients with no clinical symptoms but remaining partial radiological obstruction, and 2 failures (12.5%) which required early open surgery. Much care must be given to the ureteral stenting: one of our failures was due to extra-pelvic migration of the stent. Endopyelotomy may be considered as an efficient procedure, but long-term evaluation is still required.