To date 2 approaches have been developed for performing endopyelotomy, that is the antegrade and retrograde approaches. Experience with antegrade transnephrostomy endopyelotomy is quite large and the results have been excellent. However, the need for percutaneous nephrostomy and prolonged hospitalization have been 2 drawbacks to this approach. In contrast, experience with retrograde transureteral endopyelotomy is scant. However, a ureteroscopic approach is attractive from the standpoint of eliminating the need for a large nephrostomy tube and because of the possibility of performing this procedure on an outpatient basis or during a short hospital stay. We report our experience with antegrade and retrograde endopyelotomy in 41 patients. The hospital stay (3.4 versus 4.0 days), nephrostomy tube size (8F to 10F versus 20F to 22F) and nephrostomy tube duration (2.9 versus 3.8 days) were all less with the retrograde approach. The initial success rate was similar between the 2 methods: 79% (retrograde) versus 78% (antegrade). However, the analgesic requirements (5.3 versus 3.5 doses) and the occurrence of significant complications (that is late ureteral stricture in 20%) were greater with the ureteroscopic approach. With the methods currently available, we believe that antegrade endopyelotomy is the preferred approach for endopyelotomy.