In 2007, the Scandinavian Obesity Surgery Registry (SOReg) was started by the profession to monitor the results of bariatric surgery and to provide a high-quality database for research. In the end of August 2023, SOReg contains 88,379 patients (body mass index [BMI] 41.7 kg/m , 41.2 years, 77.1% females, gastric bypass 76.8%). In this narrative review, we demonstrate that preoperative weight loss is of value and that the laparoscopic double omega-loop technique is highly suitable for gastric bypass. Closing the mesenteric openings is, however, important. Swedish bariatric surgery has low mortality, and our results are comparative to those of other countries. Significant long-term improvements are found in common obesity-related diseases such as diabetes, hypertension, and sleep apnea. Furthermore, the risk for cardiac failure and major adverse cardiovascular events is significantly reduced. Pregnancy-related outcomes are also improved. Gastric bypass results in significant improvements in quality of life and seems to be cost saving. We have revealed that low socioeconomic status is associated with reduced chance of undergoing bariatric surgery and inferior outcomes. Of note, we have performed several randomized clinical trials within the registry database. In conclusion, high-quality national registry databases, such as SOReg, are important for maintaining high-quality care and present a platform for extensive research.