We report on a patient who presented with left flank pain for 6 months. Computed tomography and intravenous urography revealed left ureterosciatic herniation with severe hydronephrosis. Antegrade placement of the ureteral double-J stent was performed and her symptoms subsequently subsided. These symptoms recurred after the removal of the stent 1 year later with persistent hydronephrosis and herniation. We performed laparoscopic ureterolysis, ureteral fixation to psoas muscle, and sciatic hernia repair with hyaluronan-containing mesh. The result was encouraging and the follow-up image at 6 months showed no hydronephrosis and no ureteral herniation.