We were the first to initiate endopyelotomy in Hungary (in 1986) and in Yemen and Pakistan (in 1993). Through the end of 1995, 320 cases of ureteropelvic junction (UPJ) stenosis have been operated upon. The procedure was performed under local anesthesia in adult patients and general anesthesia in children. The minimum age of the patient was 4 years, while the oldest patient was 80 years of age. The UPJ was incised longitudinally at the posterolateral aspect until the perinephric fat was seen, and a drain of 8F to 12F was inserted transrenally into the ureter through a nephroscope. Patients soon left the hospital and were able to start working in 5 days (average). The drain was removed after 6 weeks. During the follow-up period, ultrasonic examination was performed each 3 months. The success rate (mean of three centers) came out to be 87%. Open pyeloplasty was performed in cases where the symptoms of pyelectasia were persisting and caused complaints and stenosis was present even after 6 months. In our opinion, endopyelotomy should be the procedure of first choice for UPJ stenosis, because it is less troublesome for the patient than open pyeloplasty, and the results are real encouraging.