INTRODUCTION AND HYPOTHESIS: We compared treatment success and adverse events between women undergoing open abdominal sacrocolpopexy (ASC) vs vaginal repair (VAR) using data from women enrolled in one of three multicenter trials. We hypothesized that ASC would result in better outcomes than VAR. METHODS: Participants underwent apical repair of stage 2-4 prolapse. Vaginal repair included uterosacral, sacrospinous, and iliococcygeal suspensions; sacrocolpopexies were via laparotomy. Success was defined as no bothersome bulge symptoms, no prolapse beyond the hymen, and no retreatment up to 24 months. Adverse events were collected at multiple time points. Outcomes were analyzed using longitudinal mixed-effects models to obtain valid outcome estimates at specific visit times, accounting for data missing at random. Comparisons were controlled for center, age, body mass index (BMI), initial Pelvic Organ Prolapse Quantification (POP-Q) stage, baseline scores, prior prolapse repair, and concurrent repairs. RESULTS: Of women who met inclusion criteria (1022 of 1159 eligibile), 701 underwent vaginal repair. The ASC group (n = 321) was older, more likely white, had prior prolapse repairs, and stage 4 prolapse (all p < 0.05). While POP-Q measurements and symptoms improved in both groups, treatment success was higher in the ASC group [odds ratio (OR) 6.00, 95% confidence interval (CI) 3.45-10.44). The groups did not differ significantly in most questionnaire responses at 12 months and overall improvement in bowel and bladder function. By 24 months, fewer patients had undergone retreatment (2% ASC vs 5% VAR); serious adverse events did not differ significantly through 6 weeks (13% vs 5%, OR 2.0, 95% CI 0.9-4.7), and 12 months (26% vs 13%, OR 1.6, 95% CI 0.9-2.9), respectively. CONCLUSIONS: Open sacrocolpopexy resulted in more successful prolapse treatment at 2 years.