Electrohydraulic lithotripsy (EHL) was employed for the treatment of 35 patients with upper urinary tract calculi. The stones in 14 patients with renal and upper ureteral calculi were disintegrated by a 9Fr probe and the rigid nephroscope. Twelve patients with upper or middle ureteral calculi were treated using a 5Fr probe and the fiberscope. The stones in 9 patients with lower ureteral calculi were removed by a 5Fr probe and the rigid ureteroscope. Although small residual stones were observed in 15 patients (43%), all the stones were fragmented satisfactorily except in two patients. The complications due to EHL were observed in eight patients (23%). The most frequent complication was the ureteral injury which was observed in 6 patients. In 2 of these patients the stone migrated out from the ureter. However, all the cases of ureteral injury were healed by the conservative therapy such as by indwelling the stent catheter without ureteral stricture.