The best procedure for the treatment of morbid obesity has not yet been defined. Biliopancreatic diversion is one of the techniques available, but its results have not been sufficiently documented and the addition of a subtotal gastrectomy to the diversion so as to avoid leaving a blind non-functioning stomach, is still questionable. The purpose of this paper is to report our experience with our first 149 consecutive patients who were treated by biliopancreatic diversion with subtotal gastrectomy for morbid obesity. Operative mortality was 3% and morbidity was 12%. The weight loss was marked during the first 6 months and decreased during the following 12 months. The weight stabilized at 2 years and there was subsequently a small increase. In only two out of 48 cases was the weight loss less than 25% of the initial weight at 2 years. The undesirable side-effects were diarrhea in 6%, vomiting in 9% and dyspepsia in 4%. The intervention leads to a malabsorption of carotene, iron, albumin and calcium. Except for carotene the deficiencies were corrected by oral supplement. In two patients, with resistant deficiencies, the diversion was reversed. Eighty-eight per cent of the patients are satisfied with this intervention. At 2 years, 70% have reached their weight loss objective without any major side-effects or nutritional deficiencies, but in 14% the outcome of the procedure must be considered unsatisfactory. Biliopancreatic diversion with subtotal gastrectomy is a major operation, but it gives encouraging results so far.