We investigated whether there are differences between the natural history of B and C chronic hepatitis in a southern Italian population, and whether the chronic viral hepatitis population was modified by the introduction of the anti-HCV test in 1989. We examined clinical charts of 1120 patients consecutively admitted to our division from January 1979 to December 1998 with the histological diagnosis of chronic viral hepatitis (304 from 1979 to 1988; 816 from 1989 to 1998). We found significant differences only in age at diagnosis (higher in the second decade, P = 0.001), and in aetiology (HBV decreased in the second decade, P < 0.0001). We were able to follow up 449 patients for 2-20 years (311 with HCV and 138 with HBV infection), and found that chronic HCV evolved to cirrhosis more frequently than did chronic HBV; but in both types time to development of cirrhosis and the incidence of death were similar. Our data confirm that a higher onset age of HBV and of HCV is frequently observed in those subjects who have a faster disease progression.