Between March 1984 and March 1986, 31 children with 42 ureters with grades IV and V primary vesicoureteric reflux were treated by endoscopic subureteric injection of Polytef paste. Reflux ceased after a single injection in 28 ureters, after the second in six, after the third in three and after the fourth injection in one. Two ureters showed improvement to grade II reflux after two injections and no further treatment was given. Two ureters showed no change in grade of reflux after three and four injections, respectively. Twenty-seven children with successfully treated ureters have now been followed up for periods ranging from 6 to 30 months. All 38 ureters had a negative micturating cystogram following endoscopic correction. At follow-up there was no reflux in 32 (84%) ureters and recurrence in six (16%). The procedure is simple to perform and without significant complications. The follow-up results show that the endoscopic treatment is reliable and effective in correcting higher grades of vesicoureteric reflux.