One Anastomosis Gastric Bypass (OAGB) has become the third most frequent bariatric/metabolic procedure worldwide. It is accepted as standard operation by the International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO), by the American Society of Surgery of Metabolic and Bariatric Surgery, and many other national bariatric societies. This success is caused by its relative simplicity, low complication rates, short operative times, a steep learning curve and last but not least by its excellent outcomes concerning weight loss and remission of comorbidities. But, as other bariatric procedures this method has specific pitfalls and longterm complications which might cause certain limitations regarding the widespred indication for OAGB. In particular, this concerns the risks of biliary reflux especially in patients with pre-existing gastroesophageal reflux disease and the effects of malabsorption like steatorrhea and nutritional deficiencies. On the other hand, OAGB is an excellent operation to be be considered in patients with very high BMI, visceral fat distribution type, and most notably with metabolic syndrome. Based on a large individual experience with this procedure, the presentation will give a more detailed view of possible good and bad indications of OAGB as primary and revisional bariatric and metabolic operation.