Subureteral injection of bulking agents is an accepted, less invasive, treatment of vesicoureteral reflux (VUR) in children. We evaluated the efficacy of an endoscopic subureteral polydimethylsiloxane (Macroplastique^®) injection with primary VUR in children. A total of 21patients (31 renal units), aged between 2 and 15 years were included in this study. The vesicoureteral reflux was grade I in 5, grade II in 7, grade III in 9, grade IV in 7 and grade V in 3 renal units. PDS was injected submucosally under the ureteric orifice, converting the opening to allow the elevation of the mucosa, so that the orifices lay on the summit of a small mound, which assumed an elevated crescent appearance by the end of the procedure. The patients were followed up from 6 to 24 months (mean 18.5 months) with voiding cystourethrography. Overall, the reflux was corrected in 26 of the renal units (83.8%) in one injection. The correction rates, according to the reflux grade, were 100, 100, 88.8, 71.4, 66.7% for grades I to V, respectively. There were no associated postoperative complications. The mean hospital stay and operation time were 2.7 days (2~4 days) and 17.5 minutes (12~25 minutes), respectively. In conclusion, for low grade reflux, subureteral PDS injection therapy could be a primary treatment for VUR in children because it is simple, less invasive, decreased hospital stay and showes a high success rate.