[en] Purpose: We analyzed the results of a prospective, observational trial designed to assess the safety and efficacy of the TVT-O procedure for female SUI. Materials and Methods: Preoperative and postoperative evaluations included physical examination, and urinary symptom and quality of life scale questionnaires. Results: Between March 2003 and December 2004, 253 patients with clinical and urodynamic diagnoses of SUI who fulfilled inclusion and exclusion criteria were enrolled in the trial and underwent the TVT-O procedure. No significant intraoperative complications were observed. One-year minimum followup was available on 99 of the initial 102 patients, of whom 16 had undergone concomitant pelvic organ prolapse surgical treatment. The SUI complete cure rate was 91%. No patient had vaginal or urethral erosion. Four patients required tape release or section. Frequency and urge symptoms improved after the operation (p < 0.001). The severity of obstructive symptoms slightly increased postoperatively in the group of patients who did not undergo associated pelvic organ prolapse treatment (p < 0.05), while maximum flow rates somewhat decreased (p < 0.001) and post-void residual urine volumes somewhat increased (p < 0.005). Most patients reported a significant decrease in incontinence severity and improvement in quality of life (p < 0.0001). Conclusions: The results of this study, which suggest that the TVT-O procedure is a safe and efficient surgical treatment for female SUI, warrant further comparative evaluation of this procedure with retropubic and outside in transobturator approaches in appropriately designed, prospective, randomized trials.