Background: The practice of bariatric surgery was studied using the German Bariatric Surgery Registry (GBSR). The focus of the study was to evaluate whether revision sleeve gastrectomy (R-SG) or Roux-en-Y Gastric Bypass (R-RYGB) has a major benefit in terms of perioperative risk in patients after failed Adjustable Gastric Banding (AGB). Methods: The data collection includes patients who underwent SG or RYGB as revision surgery after failed AGB between 2005 and 2019. Outcome criteria were perioperative complications, comorbidities, 30-day mortality, and operative time. Results: The study analyzed data from 1395 patients after revision SG and RYGB. 907 patients after R-RYGB, and 488 after R-SG. Intraoperative and overall postoperative complication rates were not significantly different between the two groups (p=0.321 and 0.621). The specific postoperative complication rate was significantly lower in R-SG than in R-RYGB (p=0.049). The mean operative time differed significantly between the two groups in favor of R-SG (160.3 min vs. 128.3 min; p<0.001). There was no significant difference in 30-day mortality between the two groups (p=0.952). Conclusion: The study shows that R-SG and R-RYGB are safe and feasible as revision procedures and have acceptable complication and mortality rates. However, in our study, we cannot make a recommendation in favor of any of the surgical methods. Proper patient selection is essential to avoid possible adverse effects. Concerning the long-term results, further studies with higher methodological quality are necessary.