The hepatitis C virus (HCV) infection may change the outcome of patients undergoing stem cell transplantation. This study aimed at determining the prevalence of the HCV antibody in patients who were alive 10 or more years after BMT, defining the annual progression rate of hepatic fibrosis in those patients, and identifying cases of cirrhosis among those who were positive for HCV antibody. Between 1979 and 1990, 259 patients had a bone marrow transplant, and 91 were alive in March 2000. Of those, 80 were included in the study after having been scanned for serum HCV antibodies. A total of 39 were positive (48.8%), one was indeterminate and 40 were negative (50%). The patients who were HCV positive or undetermined were called for a medical appointment and 22 (55%) attended. A total of 16 patients (72.7%) were male, the mean age was 37.8+/-9.2 years and all of them had had an allogeneic transplant. Of the 22 patients studied, 12 (54.5%) agreed to have a liver biopsy. Hepatic fibrosis was diagnosed in 10 patients. The hepatic fibrosis annual progression rate was 0.156 UF/year. Among the anti-HCV-positive patients assessed, three (13.6%) already had cirrhosis.