We assessed the results of endourologic treatment of patients with a primary ureteropelvic junction obstruction (UPJO) caused by high insertion of the ureter into the renal pelvis (HIUPJO). A total of 10 patients 15 to 76 years old with preoperatively diagnosed HIUPJO were treated. Acucise retrograde endopyelotomy was performed in eight patients and percutaneous antegrade endopyelotomy in two. A stent was left in place for an average of 5.3 weeks. The subjective success rate, based on patient questionnaire and analog pain scales, was 80% at 27 months' average follow-up. The objective success rate, based on diuretic renal scanning or Whitaker test, was 70% at 26 months' mean follow-up. Overall, 60% of the patients had both an objectively and a subjectively successful outcome. The success rate for endopyelotomy in patients with UPJO caused by high insertion is similar to that reported for endopyelotomy in patients without high insertion. High insertion is not a contraindication to endopyelotomy.