OBJECTIVE To prospectively evaluate the efficacy of endoscopic injection in the adult population with vesicoureteral reflux (VUR). The search for VUR is a part of the standard workup of children with febrile urinary tract infections. However, VUR can present later in life and should be investigated in the case of recurrent pyelonephritis. METHODS From 2005 to 2009, 27 postpubertal patients (3 males and 24 females) were treated endoscopically with injection of polydimethylsiloxane (Macroplastique) in 13 or dextranomer/hyaluronic acid copolymer (Deflux) in 14 patients; 41 renal units were injected. The median age was 23 years (range 12-65). The VUR was evaluated as grade I in 5 ureters, grade II in 28, grade III in 7, and grade IV in 1. The indications for surgery were recurrent pyelonephritis in all patients, except for 1. Of the 27 patients, 5 (12%) had undergone previous ureteral surgery. The patients were followed up with renal ultrasonography and voiding cystourethrography. RESULTS VUR was corrected in 38 (93%) of 41 ureteral units. Of the 3 failures, 1 patient had a large Hutch diverticulum and another had previously undergone ureterocele incision. All the patients with treatment failure had been injected with dextranomer/hyaluronic acid copolymer. Thus, the success rate was 100% with polydimethylsiloxane and 87% with dextranomer/hyaluronic acid copolymer. De novo hydronephrosis appeared in 1 renal unit. The obstruction was confirmed by a mercaptoacetyltriglycine-Lasix technetium-99m scan and treated with temporary diversion using a double-J stent. CONCLUSIONS Endoscopic injection is an effective treatment of VUR after puberty. In cases of recurrent pyelonephritis, imaging should be mandatory to detect scars and VUR because the endoscopic treatment is simple and noninvasive and has a good success rate, comparable to that reported for children.