Jejunoileal bypass has been the subject of over 350 reports in the literature. The initial enthusiasm for massive intestinal bypass seems to be declining because of its association with numerous and occasionally severe or fatal complications. In the past 9 years, there have been 800 jejunoileal bypass procedures performed at the University of Minnesota. A specific protocol for preoperative, intraoperative, and postoperative care has been, devised to minimize the perioperative and long-term morbidity and mortality. The most frequent complications in the immediate postoperative period were urinary tract infection (11.9%), wound infection (6%), and thrombophlebitis (2.9%). There were 2 deaths which occurred in the early postoperative period. In our patient series, 80.5% sustained a weight loss in excess of 30 kg by 1 year. This weight loss has been associated with many beneficial effects including reduction in serum lipid levels, blood pressure, and blood sugar in the diabetic patients. There has also been a marked improvement in self-esteem and socialization. The severe adverse sequelae of jejunoileal bypass have occurred in approximately 8%-10% of our patients. Many of the electrolyte and liver dysfunction problems have been minimized by close and frequent follow-up. Fatigue (8%), cholelithiasis (4%), urolithiasis (9%), and bypass enteritis (10%) have been other adverse results of massive intestinal bypass. There were 5 additional deaths (total mortality rate of 1%) in our series related to sepsis and/or hepatic failure. The reanastomosis rate has been under 2% in our series to date.