Twenty-eight patients (19 females, 9 males) were evaluated pre- and posttransplant to determine the frequency and find predictors of excessive weight gain after orthotopic liver transplant. Posttransplant, 21 patients gained and 7 patients lost weight as compared with their pretransplant dry weight. The majority of weight gain occurred between 2 and 16 months; 64.3% of patients (18/28 pts.) became overweight. All patients overweight prior to transplant (11 pts.) were more overweight posttransplant (P <0.005). Overweight and non-overweight patients were similar in age, female predominance, etiology of liver disease, hypercholesterolemia, and hypertriglyceridemia pretransplant, as well as diabetes mellitus and medications including prednisone posttransplant. Overweight patients more commonly had a family history of diabetes mellitus, arteriosclerotic heart disease, and hypertension. They also had more hypertension, hypercholesterolemia, hypertriglyceridemia, abnormal physical findings related to the liver, and abnormal results of hepatic tests posttransplant. Mean rate of weight gain for overweight patients compared with nonoverweight ones during the first 16 months after transplant was 1.5 kg/month ±0.9 vs. 0.4 kg/month ±0.4 for those not overweight. After 16 months mean rate of increase was slower for overweight patients (0.3 kg/month ±0.3), whereas weight appeared to stabilize in the nonoverweight ones. We conclude that excessive weight gain after liver transplant is common and occurs early. Since obesity may contribute to, as well as be a separate cause, of hepatic abnormalities, confusion may result when interpreting abnormal results of hepatic tests. Obesity prior to transplant predicts excessive weight gain posttransplant, although all patients may be at risk.