PURPOSE: We determined the prognostic value of preoperative urodynamic results in patients with stress urinary incontinence. MATERIALS AND METHODS: In a 9-center surgical trial, women with stress urinary incontinence were randomized to a Burch or pubovaginal sling procedure. Women were eligible for the study if they had predominant stress urinary incontinence symptoms, a positive cough stress test, a bladder capacity more than 200 ml and urethral hypermobility. Preoperative free uroflowmetry, filling cystometry and pressure flow studies were performed in all. Overall treatment success required a negative pad test, no urinary incontinence on a 3-day diary, a negative stress test, no self-reported stress urinary incontinence symptoms and no re-treatment for stress urinary incontinence. Stress specific success required all of the last 3 criteria. We examined urodynamic measures, and whether the presence of urodynamic stress incontinence, the presence of detrusor overactivity and Valsalva leak point pressure would predict surgical success. RESULTS: Subjects with urodynamic stress incontinence had a 2-fold greater odds of overall success when compared with the No urodynamic stress incontinence group, but this trend did not quite reach statistical significance (OR 2.26; 95% C.I. 0.99, 5.17). Odds of stress specific success did not differ by urodynamic stress incontinence status. Subjects with detrusor overactivity did not have significantly worse success rates. Stratifying by treatment group, there was no difference in mean Valsalva leak point pressure values between surgical successes and failures. CONCLUSIONS: We found a nearly statistically significant trend that women with urodynamic stress incontinence are twice as likely to have a successful overall outcome from surgical management of stress urinary incontinence as women without urodynamic stress incontinence. The level of Valsalva leak point pressure and the presence of detrusor overactivity do not predict the success outcomes after the Burch or autologous fascia sling procedures in women with pure or predominant stress urinary incontinence. The impact of urodynamic studies on surgical outcomes needs further investigation.