The extent of serious complications in people who have acquired chronic hepatitis C infection after a blood transfusion is unclear.We studied 131 patients with chronic post-transfusion hepatitis C who were referred to our center between February 1980 and June 1994. Eighty-two other patients were excluded because they had multiple transfusions, hemophilia, intravenous drug use, human immunodeficiency virus infection, hepatitis B infection, hemochromatosis, or alcoholic liver disease. Liver biopsies were performed in 101 patients; biopsies were not performed in the other 30 patients, all with signs of cirrhosis, because the results of coagulation tests were abnormal.The mean age of the patients was 57 years (range, 21 to 81) at the time of our initial evaluation. The mean age at the time of the blood transfusion was 35 years (range, 1 to 76). The mean duration of follow-up after presentation to us was 3.9 years (range, 1 to 15). Eighty-eight of the patients (67.2 percent) initially had fatigue, and 89 (67.9 percent) had hepatomegaly. Twenty-seven patients (20.6 percent) initially had chronic hepatitis, 30 (22.9 percent) had chronic active hepatitis, 67 (51.1 percent) had cirrhosis, and 7 (5.3 percent) had hepatocellular carcinoma. Hepatocellular carcinoma developed in an additional seven patients an average of 36 months (range, 7 to 121) after the initial visit. During follow-up, 20 patients (15.3 percent) died: 8 from complications of cirrhosis (1 after a liver transplantation); 11 from hepatocellular carcinoma; and 1, with chronic active hepatitis, from pneumonia.In a group of patients seen at a referral center, chronic post-transfusion hepatitis C was a progressive disease and, in some patients, led to death from either liver failure or hepatocellular carcinoma.