In a randomized trial, we compared the success of Burch retropubic urethropexy to the modified anterior colporrhaphy for the treatment of genuine stress urinary incontinence. Thirty-five patients with stress incontinence were randomly assigned to undergo Burch retropubic urethropexy or modified anterior colporrhaphy. Subjects had preoperative and 1-year postoperative physical examinations, multichannel urodynamic testing, 20-minute pad test, and subjective grading of incontinence severity with questionnaires. Data were evaluated using Fisher exact test, Wilcoxon two-sample test, logistic regression analysis, and analysis of variance. Objective cure 1 year postoperatively was significantly greater for the women treated by Burch retropubic urethropexy than by modified anterior colporrhaphy (16 of 18 [89%] versus five of 16 [31%], relative risk .15, 95% confidence interval .04, .59). Patients' subjective ratings of incontinence severity 1 year after surgical treatment were significantly lower in women who had Burch retropubic urethropexy. Burch retropubic urethropexy yields a significantly superior objective cure for genuine stress urinary incontinence than the modified anterior colporrhaphy in a randomized trial.