Aim: To evaluate the effects of tension-free vaginal tape (TVT) and tension-free vaginal tape-obturator (TVT-O) operations on urodynamics and subjective and objective outcomes. Materials and Methods: Thirty-six patients with stress or mixed urinary incontinence underwent TVT or TVT-O. Bristol Female Lower Urinary Tract Symptoms (BFLUTS) Questionnaire-Scored Form, one-hour pad test, Q-tip test, perineometer, and urodynamics were performed before and after the operations. Blaivas-nomogram was used for assessment of postoperative voiding difficulty. Results: Nineteen patients underwent TVT-O and 17 patients underwent TVT. Mean follow-up was 18.4 +/- 6.8 months. There was no difference between two groups regarding demographic variables, degree of prolapse, type of incontinence, perineometer, Q-tip test, pad test, and urodynamics. There was a significant increase in the maximum urethral closure pressure (MUCP) and residual volume in TVT-O group. According to Blaivas-nomogram, five patients had mild, one had medium obstruction in the TVT-O group, whereas one had mild and three had medium obstruction in TVT group. Two bladder perforations occurred during TVT. One patient developed groin pain after TVT-O. Conclusions: TVT-O may lead to an increase in MUCP and residual urine volume. TVT-O is as efficient as TVT and leads to milder obstruction when compared to TVT.