There are several surgical approaches to treat obesity not cured with medical approaches. Each method has its advantages and complications. In here, we have conducted a study to evaluate complications of biliointestinal bypass surgery (BIBP).  A prospective study was conducted in a private hospital from 2002 to 2016. Those patients, not previously operated for morbid obesity, were eligible. Mean follow-up period was 89 months ( ± 54 months; range: 73-108 months). Main outcome measures were weight, BMI (body mass index), concentrations of blood lipids and glucose, liver transaminases, and obesity-related comorbidities and complications.  Twenty-three consecutive patients with morbid obesity, including 16 women (69.7%) and seven men (31.3%) with mean age 38.47 ± 10 years (range: 26-57 years) underwent surgery. At the end of follow-up period, a mean BMI reduction of 12.2 kg/m kg/m ( < 0.001)] was observed. An excess weight loss (EWL) of 63% ( ± 34) was achieved at the end of the study. Additionally, total cholesterol and triglyceride levels decreased postoperative significantly. The main long-term complications were flatulence (60%), borborygmus (47.8%), mal odorous stool (30.4%), and diarrhea (21.7%). Revision rate was 4.34%. There were no cases with irreversible hepatic injury, deaths due to the surgery, or progressive renal failure. BIBP seems to be a safe, easily reversible, and one of valid therapeutic approaches in morbidly obese patients. BIBP has the potential to achieve durable weight loss and offers an improved quality of life.