Background: The benefits of presurgery weight management programs (WMPs) for bariatric patients are mixed; some show a positive impact on percent excess weight loss (%EWL) at 12 months postsurgery, while others show no effect. Objectives: The purpose of this study was to compare pre- and postoperative 6- and 12-month outcomes between patients who attended a 12-week presurgery WMP and patients who did not participate. Setting: Ohio State Wexner Medical Center, University Hospital, United States. Methods: A retrospective medical record analysis was conducted to compare preoperative and 6- and 12-month postoperative outcomes for patients who attend the presurgery WMP (n = 56) and patients who did not (n = 441) within a 2-year time period (N = 497). Descriptive statistics and independent t tests were conducted to determine mean differences between groups, while controlling for surgery type, for weight status outcomes (%EWL, change in body mass index) preoperatively and 6 and 12 months postsurgery, and length of stay and readmission rate. Results: Patients who attended the preoperative WMP had significantly higher %EWL at 12 months postsurgery compared with patients who did not attend the WMP. Additional findings indicated a positive, but nonsignificant effect, from the WMP on presurgery body mass index, and postsurgery %EWL at 6 months and body mass index change at 6 and 12 months postsurgery. Conclusions: Patients attending the WMP had better 12-month %EWL and outcomes compared with those who did not attend the WMP, though this was not true for 6-month outcomes and differed based on surgery type. (Surg Obes Relat Dis 2018;14:1714–1724.) Published by Elsevier Inc. on behalf of American Society for Bariatric Surgery.