Two women, aged 41 and 51 years, developed jaundice, encephalopathy, and hypoprothrombinemia during rapid weight loss four and 12 months after jejunoileal bypass for refractory obesity. Both were treated for liver failure and received a prolonged course of nutrition parenterally and orally. Serial liver biopsy specimens demonstrated extensive alcoholic-like hepatitis and cirrhosis that improved with nutritional repletion and reanastomosis. Postoperative biopsy specimens later demonstrated minimal portal fibrosis in one patient and inactive mild cirrhosis in the other. Although previous reports indicate that patients usually die when they develop liver failure of this severity after jejunoileal bypass, prolonged intensive nutritional repletion was associated with sufficient clinical and histologic improvement in these two patients so that intestinal reanastomosis could be performed safely. © 1979 American Medical Association. All rights reserved.