Background and Design.- We retrospectively re¬viewed the records of 68 female patients who un¬derwent either Pubovaginal Sling (PVS) or Modifi¬ed Raz "Anterior Vaginal Wall Sling (AVWS) opera¬tions between December 1993 and March 1999, in order to determine the role and importance of endoscopic controls during transvaginal bladder neck suspension and sling operations for stress urinary incontinence. AVWS was performed in 22 and PVS in 46 patients. Endoscopic controls were performed before the sutures were tied over the rectus fascia. Bladder wall, bladder neck and the position of the balloon of the cystostomy catheter were examined and the ureters were catheterized in order to ensure that no ureteric injury occurred. Results.- Bladder neck perforation was detected in 2 patients and repaired accordingly. In 2 pati¬ents ureteric entrapment by the sutures was de¬tected and the sutures were replaced. In 1 patient the balloon of the cystostomy catheter was found outside the bladder and the catheter was reinser¬ted. One patient, whose cystostomy catheter was not controlled during cystoscopy, developed seve¬re suprapubic pain postoperatively, on reexamina-tion it was found that the balloon of the cystos¬tomy catheter was placed outside the bladder. Inadequate drainage of the bladder during the operation was responsible for the injury in one of the 2 patients who suffered bladder neck perfora¬tion. Concomitant cystocele repair was performed in both of the patients whose ureters were en¬trapped. Conclusion.- Concomitant cystocele repair and inadequate bladder drainage are factors that inc¬rease the risk .of intraoperative complications. En¬doscopic control is mandatory in sling and trans-vaginal suspension operations for early recogniti¬on and appropriate repair of such complications.