We reviewed our experience with endoscopic sub-ureteral injection of polytetrafluoroethylene (PTFE) in 337 children (84% females, 16% males). Four hundred and ninety one refluxing ureters were injected (93% primary reflux, 7% secondary reflux after reimplantation, correction of exstrophy of the bladder or neurogenic bladder). Reflux was: - stage I: 7.8% - stage II: 32% - stage III: 38% - stage IV: 20% - stage V: 2.2% Follow-up cystograms were performed one 428 ureters, 6 to 30 months after injection. 80% of children are cured after one injection while 4% required two injections in order to attain the same result. Improvement in the grade of reflux (minimal residual disease) was noted in 10% of the patients and in 6% the procedure failed. In the latter group, 16 children were operated on without difficulty; lymphatic migration of PTFE was noted in two cases. In the 33 patients with secondary reflux, the endoscopic treatment was associated with an 80% cure rate, in the 26 patients presenting a reflux on duplex systems, cure rate was 65%. This is a simple procedure performed on an outpatient basis; in our experience with 491 injections there were no complications at the time of injection nor there any postoperative ureteric obstruction. Endoscopic PTFE injections are less efficient than surgical reimplantation in the treatment of vesico-ureteral reflux. Teflon paste may not be the ideal material, other substances are presently being investigated. This technic is limited by the caliber of the urethra in young boys (Charrière 14).