© 2007 Massachusetts Medical Society. All rights reserved. Background Many surgical procedures are available for women with urinary stress incontinence, yet few randomized clinical trials have been conducted to provide a basis for treatment recommendations. Methods We performed a multicenter, randomized clinical trial comparing two procedures — the pubovaginal sling, using autologous rectus fascia, and the Burch colposuspension — among women with stress incontinence. Women were eligible for the study if they had predominant symptoms associated with the condition, a positive stress test, and urethral hypermobility. The primary outcomes were success in terms of overall urinary-incontinence measures, which required a negative pad test, no urinary incontinence (as recorded in a 3-day diary), a negative cough and Valsalva stress test, no self-reported symptoms, and no retreatment for the condition, and success in terms of measures of stress incontinence specifically, which required only the latter three criteria. We also assessed postoperative urge incontinence, voiding dysfunction, and adverse events. Results A total of 655 women were randomly assigned to study groups: 326 to undergo the sling procedure and 329 to undergo the Burch procedure; 520 women (79%) completed the outcome assessment. At 24 months, success rates were higher for women who underwent the sling procedure than for those who underwent the Burch procedure, for both the overall category of success (47% vs. 38%, P = 0.01) and the category specific to stress incontinence (66% vs. 49%, P<0.001). However, more women who underwent the sling procedure had urinary tract infections, difficulty voiding, and postoperative urge incontinence. Conclusions The autologous fascial sling results in a higher rate of successful treatment of stress incontinence but also greater morbidity than the Burch colposuspension.