IMPORTANCE: More than 300,000 surgeries are performed annually in the United States for pelvic organ prolapse. Sacrospinous ligament fixation (SSLF) and uterosacral ligament suspension (ULS) are commonly performed transvaginal surgeries to correct apical prolapse. Little is known about their comparative efficacy and safety, and it is unknown whether perioperative behavioral therapy with pelvic floor muscle training (BPMT) improves outcomes of prolapse surgery. OBJECTIVE: To compare outcomes between (1) SSLF and ULS and (2) perioperative BPMT and usual care in women undergoing surgery for vaginal prolapse and stress urinary incontinence. DESIGN, SETTING, AND PARTICIPANTS: Multicenter, 2 × 2 factorial, randomized trial of 374 women undergoing surgery to treat both apical vaginal prolapse and stress urinary incontinence was conducted between 2008 and 2013 at 9 US medical centers. Two-year follow-up rate was 84.5%. INTERVENTIONS: The surgical intervention was transvaginal surgery including midurethral sling with randomization to SSLF (n = 186) or ULS (n = 188); the behavioral intervention was randomization to receive perioperative BPMT (n = 186) or usual care (n = 188). MAIN OUTCOMES AND MEASURES: The primary outcome for the surgical intervention (surgical success) was defined as (1) no apical descent greater than one-third into vaginal canal or anterior or posterior vaginal wall beyond the hymen (anatomic success), (2) no bothersome vaginal bulge symptoms, and (3) no re-treatment for prolapse at 2 years. For the behavioral intervention, primary outcome at 6 months was urinary symptom scores (Urinary Distress Inventory; range 0-300, higher scores worse), and primary outcomes at 2 years were prolapse symptom scores (Pelvic Organ Prolapse Distress Inventory; range 0-300, higher scores worse) and anatomic success. RESULTS: At 2 years, surgical group was not significantly associated with surgical success rates (ULS, 59.2% [93/157] vs SSLF, 60.5% [92/152]; unadjusted difference, -1.3%; 95% CI, -12.2% to 9.6%; adjusted odds ratio [OR], 0.9; 95% CI, 0.6 to 1.5) or serious adverse event rates (ULS, 16.5% [31/188] vs SSLF, 16.7% [31/186]; unadjusted difference, -0.2%; 95% CI, -7.7% to 7.4%; adjusted OR, 0.9; 95% CI, 0.5 to 1.6). Perioperative BPMT was not associated with greater improvements in urinary scores at 6 months (adjusted treatment difference, -6.7; 95% CI, -19.7 to 6.2), prolapse scores at 24 months (adjusted treatment difference, -8.0; 95% CI, -22.1 to 6.1), or anatomic success at 24 months. CONCLUSIONS AND RELEVANCE: Two years after vaginal surgery for prolapse and stress urinary incontinence, neither ULS nor SSLF was significantly superior to the other for anatomic, functional, or adverse event outcomes. Perioperative BPMT did not improve urinary symptoms at 6 months or prolapse outcomes at 2 years. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00597935.