PURPOSE: To evaluate the efficacy of subureteral injection types in patients with middle- to high-grade vesicoureteral reflux (VUR). MATERIALS AND METHODS: Between June 1999 and September 2010, subureteral dextranomer was applied at our clinic to 149 patients (214 refluxing ureters) with grades II, III, and IV VUR. Group 1 consisted of 54 patients (80 ureters), and group 2 consisted of 95 patients (134 ureters). The standard subureteric transurethral injection (STING) procedure was applied to group 1, and the modified STING procedure was applied to group 2. A second and if needed a third injection was applied to unsuccessfully treated patients. The mean follow-up period was 2 years. Patients were evaluated by cystography and ultrasonography in the third month of follow-up. RESULTS: VUR was resolved completely after a single injection in 54/80 ureters (67.5%) in group 1 and in 94/134 ureters (70.1%) in group 2. Overall successes after a second or a third injection were 61/80 (76.2%) and 111/134 (82.8%), respectively. There was a statistically significant difference between the groups only for grade IV reflux following multiple injections (p<0.05). CONCLUSIONS: Endoscopic treatment of VUR is a recommended treatment because it is minimally invasive, efficient, and repeatable. Our study confirmed that a modified STING procedure can be an alternative treatment to the standard technique.