BackgroundRoux-en-Y gastric bypass (RYGB) is the gold standard in bariatric surgery. The one-anastomosis gastric bypass (OAGB) procedure, first introduced by Dr. Rutledge, has demonstrated a 25% greater weight loss efficiency than the traditional Roux-en-Y gastric bypass (RYGB) procedure due to the substantially longer biliopancreatic limb (BPL).Aim of the studyThe current work aimed to compare the outcomes of OAGB and long BPL RYGB regarding weight loss and comorbidity resolution.Patients and methodsThis randomized controlled trial was done at our institution between September 2019 and January 2021. Patients who were candidates for bariatric surgery were randomly and equally allocated to two groups. Group A underwent OAGB, while group B underwent long BPL RYGB. Patients were followed up for 6 months postoperatively.ResultsThis study included 62 patients equally allocated to OAGB or long BPL RYGB, with no dropouts during follow-up. At 6 months, there was no statistically significant difference between the two groups regarding postoperative BMI (P= 0.313) and the EBWL (P= 0.238). There was comparable remission of diabetes mellitus (P= 0.708), hypertension (P= 0.999), OSA (P= 0.999), joint pain (P= 0.999), and low back pain (P= 0.999). Seven patients in the OAGB group experienced reflux symptoms (P= 0.011), which were managed by proton pump inhibitors.ConclusionExtending the BPL in RYGB provides weight loss and comorbidity remission comparable to that of OAGB. Some OAGB-related reflux cases remain a concern. However, they were sufficiently controlled with PPIs. Due to OAGB superior technical simplicity, long BPL RYGB should be preserved for cases whom are more risky for bile reflux.Graphical Abstract