To compare two anti-incontinence operations: the tension-free vaginal tape (TVT) and the TVT-Obturator for the first two 75-patient groups.One surgeon operated on two patient groups with urodynamically proven urinary stress incontinence. The first 75-patient group in 1998 included the first TVT procedures performed according to Ulmsten [Ulmsten U, Henriksson L, Johnson P, Varhos G. An ambulatory surgical procedure under local anesthesia for treatment of female urinary incontinence. Int Urogynecol J 1996;7:81-6]. Follow-up lasted for 5-6 years. The second 75-patient group in 2004 included the first TVT-Obturator operations performed according to [De Leval J. Novel surgical technique for the treatment of female stress urinary incontinence: transobturator vaginal tape inside-out. Eur. Urol. 2003;44:724-30]. Follow-up lasted for 6-13 months.The two patient groups were similar from the demographic and therapeutic points of view. The TVT-Obturator procedure required neither bladder catheterization nor intra-operative diagnostic cystoscopy. TVT-related bladder penetration (8.0%), post-operative voiding difficulties (5.0%), intra-operative bleeding (4.0%), post-operative field infection (2.7%), and post-operative pelvic floor relaxation (1.3%) were not noted with the TVT-Obturator. The early therapeutic failure rates were 2.7% for the TVT and 1.3% for the TVT-Obturator, and neither bowel nor urethral injuries were recorded.The surgeons' learning curves of these two minimally invasive surgical procedures for the treatment of female urinary stress incontinence are comparable. The safety and cost-effectiveness of the TVT are well-established. The TVT-Obturator, a novel mid-urethral sling, was designed to overcome some of the TVT-related operative complications. The TVT-Obturator patients seem to have less intra-operative and post-operative surgical complications than the TVT patients. However, long-term comparative data collection is required prior to drawing solid conclusions concerning the superiority of one of these two operative techniques.