The popularity of minimally invasive surgical techniques, such as endopyelotomy, has increased markedly among urologists in recent years. While it was initially thought that this procedure was best utilized in patients with secondary UPJ obstruction, recent evidence suggests that endopyelotomy should be considered in the majority of cases. The primary contraindication to endoscopic incision of the UPJ is a long stricture, although a large redundant renal pelvis and the presence of crossing lower pole vessels are considered by some to be relative contraindications as well. Although the majority of surgeons have used a percutaneous, antegrade approach to endopyelotomy, successful results also have been reported with a ureteroscopic, retrograde technique. With the development of modified ureterotomes and balloon-cutting devices, the retrograde approach eventually may become the preferred method since no skin incision or external drainage are needed. The role of endopyelotomy in children remains undefined. While successful results have been reported in infants, the relative morbidity and long-term success of open pyeloplasty in this age group are excellent, thus limiting the relative advantage of an endoscopic approach. However, there may be a role for endopyelotomy in older children and in those patients with secondary obstruction who have failed open surgery. From a technical standpoint, there are several minor variations in surgical technique and postoperative management that are important. The success rate of endopyelotomy using a cold knife or small electrocautery probe appears to be comparable, and the use of cautery may allow for precise control of minor bleeding thus decreasing the risk of complications. However, larger electrodes may induce greater tissue reaction leading to fibrosis and should be avoided. Postoperatively, most authors prefer a tapered double-pigtail stent which allows for adequate internal drainage while avoiding excessive pressure within the distal ureter. While successful results have been reported with stenting intervals of only four days, it is generally recommended that the stent be left in place for a minimum of six weeks following endoscopic incision of the UPJ. Overall, endopyelotomy is associated with shortened hospitalization, more rapid return to normal activity levels, and decreased morbidity compared with open pyeloplasty. The success rates reported with endopyelotomy approach those achieved with open surgery, and it is likely that an endoscopic approach to UPJ obstruction will assume an increasingly greater role in the future.