In 1990 Scopinaro’s technique of biliopancreatic diversion with distal gastrectomy (DG) and gastroileostomy was modified. A sleeve gastrectomy with duodenal switch (DS) was used instead of the distal gastrectomy; and the length of the common channel was made 100 cm instead of 50 cm. A questionnaire and a prescription for blood work were sent to 252 patients who underwent DG a mean 8.3 years ago (range 6–13 years) and 465 patients who underwent DS 4.1 years ago (range 1.7–6.0 years). The questionnaire response rate was 93%, and laboratory work was completed for 65% of both groups. The mean weight loss after DG was 37 ± 21 kg and after DS 46 ± 20 kg. There were fewer side effects after DS: The number of daily stools was lower ( p < 0.0002), as was the prevalence of diarrhea ( p < 0.01), vomiting ( p < 0.001), and bone pain ( p < 0.001). Greater benefits related to several aspects of life were reported after DS than DG ( p < 0.0001). The mean serum levels of ferritin, calcium, and vitamin A were higher ( p < 0.001), and parathyroid hormone was lower. The yearly revision rate for excessive malabsorption was 1.7% per year after DG and 0.1% per year after DS. The two procedures were equally efficient for treating co-morbid conditions such as diabetes, hypertension, and hypercholesterolemia. Biliopancreatic diversion with sleeve gastrectomy/duodenal switch and a 100-cm common limb was shown to produce greater weight loss with fewer side effects.