question: AIM To examine the association between the certification as bariatric surgery center and volume and patient outcome, data collected in the German Bariatric Surgery Registry were evaluated. All data were registered prospectively in cooperation with the Institute of Quality Assurance in Surgery at Otto-von-Guericke University Magdeburg. METHODS Data collection began in 2005 for all bariatric procedures in an online database. Participation in the quality assurance study is required for all certified bariatric surgery centers in Germany. Descriptive evaluation and matched pairs analysis were performed. Patients were matched via propensity score taking into account BMI, age, and incidence of comorbidities. RESULTS During the period from 2005 to 2013, 3083 male and 10,639 female patients were operated on with the RYGB primary approach. In Centers of Competence (77.2 %) and non-accredited hospitals (76.3 %), the proportion of female patients was significantly lower than in Centers of Reference/Excellence (78.7 %; p = 0.002). The mean age in Centers of Reference/Excellence (41.2 years) was significantly lower than in Centers of Competence (43.2 years; p < 0.05). Propensity score analysis was performed to compare matched patients with regard to BMI, age, and incidence of comorbidities. The rate of general and surgical postoperative complications and mortality rate was significantly lower in certified Centers of Reference/Excellence compared to Centers of Competence with 29 and non-certified hospitals. CONCLUSION There is evidence of improved patient outcome in certified bariatric surgery centers with higher volume. The study supports the concept of certification. There are different factors which can and cannot be preoperatively modified and influence the perioperative outcome.