Objective: To determine the risk factors leading to failure of the tension-free vaginal tape (TVT), which is an efficient procedure for the surgical treatment of stress incontinence and stress-predominant mixed incontinence. Methods: This study included 195 patients who underwent TVT surgery for the treatment of stress incontinence and mixed urinary incontinence at our hospital between 2012 and 2016 and who were not lost to follow-up. In the postoperative period, the two groups of patients, those with or without improved incontinence symptoms upon straining in the upright position, were compared in terms of age, parity, body mass index (BMI), menopausal status, types of urinary incontinence, Valsalva leak point pressure (VLPP), and the elapsed time after surgery. Results: Of the 195 patients who had incontinence upon straining in the upright position preoperatively, 24.6% continued to experience urinary leaks in the postoperative period. After TVT application, no significant differences were found between the continent and incontinent patient groups in terms of age, BMI, follow-up duration, and menopausal status, whereas mixed urinary incontinence and low VLPP values (VLPP≤60cm H 2 O) were determined as independent risk factors for failure after TVT application (p<0.05). Conclusion: The presence of intrinsic sphincter deficiency (VLPP≤60cm H 2 O) and mixed urinary incontinence are significant risk factors leading to failure of TVT surgery in the postoperative period.