Ureterorenoscopy has become a popular diagnostic and therapeutic tool for the modern urologist but this procedure is not without complications and risks. The technique may result in perforation of the ureter and subsequent stricture formation in some cases. In this study a ureteral perforation rate of 17 per cent was noted after 142 ureteroscopic procedures, with stricture formation occurring in 5 per cent. The type of dilation, reason for the procedure or placement of a postoperative stent did not seem to affect the formation of stricture but the location of the injury appeared to be significant. Of those injuries not requiring immediate surgical repair perforations within the pelvis (6 of 11) led to strictures more often than those beyond the pelvis (1 of 9). Treatment of the strictures with either an open repair or percutaneous antegrade dilation was successful.