Laparoscopic one-anastomosis gastric bypass is a new bariatric surgery technique for weight loss in morbid obesity. This technique has come to be associated with suitable weight loss results, low technical complications, short surgery time, low cost, short post-operational period, and low chances of injury comparisons with other bariatric surgical approaches to weight loss in morbid obesity such as sleeve and Roux-en-Y gastric bypass. To the best of our knowledge, there has been no report of such surgery in the case of situs inversus totalis concurrent with morbid obesity.The patient was a 36-year-old male suffering from morbid obesity (BMI, 56.8) along with situs inversus totalis. In spite of operational complexities due to the reversed location of abdominal and thoracic organs, the operation was performed similarly to routine subjects considering the diverse site of organs.Given the considerable superiorities of one anastomosis gastric bypass over other bariatric surgical techniques, particularly concerning the simpler procedure, low surgical complication and short surgery time, this approach may guarantee positive outcomes in subjects with concurrent situs inversus totalis and morbid obesity.