BACKGROUND: Vertical banded gastroplasty (VBG) presents a significant rate of long-term complications, and revisions are often necessary. Conversion to Roux-en-Y gastric bypass (RYGB) seems to be preferred, but literature data remain limited. OBJECTIVES: To analyze the indications, safety, results of conversions from VBG to RYGB, and to identify predictive factors of success or failure. SETTING: Two specialized centers of bariatric surgery. METHODS: This bicentric retrospective study included all the patients who benefited from a conversion from VBG to RYGB between 2008 and January 2020. Demographic characteristics, indications, preoperative workups, intraoperative data, complications, and weight loss results were analyzed. RESULTS: During the study period, 85 patients underwent a conversion to RYGB. The mean body mass index (BMI_ before conversion was 40.6 kg/m(2). 82.3% of the patients were converted because of weight loss failure and 17.6% because of a complication of their VBG. The global rate of complications was 25%. After an average follow-up of 35 months and a rate of loss to follow-up of 33%, the mean BMI was 33.5 kg/m. The weight loss success rate according to Reinhold's criteria was 64.7%, and resolution of complications was obtained in 89.1%. The association of a fundectomy was a predictive factor of weight loss (odds ratio, .27; P = .04), whereas primary failure of the VBG was a predictive factor of failure. CONCLUSION: Conversion from VBG to RYGB remains the procedure of choice to achieve satisfying weight loss and resolution of functional complications. The addition of a fundectomy appeared to have a significant positive impact on weight loss outcomes.