New therapeutic options for obesity include restrictive bowel surgery and surgery that promotes malabsorption, such as the Fobi-Capella (gastric bypass) and Scopinaro (biliopancreatic diversion) techniques. Complications associated with these procedures, such as hepatocellular failure, have been observed with increasing frequency. Reported here are 3 patients who, 7 to 24 months after bariatric surgery, developed hepatocellular failure, for which liver transplantation was considered to be indicated. Liver transplantation was undertaken in 2 of the patients; the third patient died while waiting for this procedure. We discuss the possible causes of this uncommon and poorly understood complication of surgery for obesity. One possibility is that it might arise as a result of progression of steatohepatitis. An alternative concept is that this complication may be secondary to rapid, massive loss of body weight.