Incidence, clinical course and outcome of viral hepatitis was evaluated during a 42 mo. study in 118 Thalassaemia minor patients, compared with a paired group of 123 nonthalassaemic subjects, matched for age, sex and number of drug addicts. In the thalassaemics, which account for 13% of residents in our area, acute hepatitis showed to have an incidence of 1.3-1.7 higher than the control group. The acute course was milder and more protracted and the number of evolution into chronicity was more elevated: 19.7% vs. 11.3%, following hepatitis B, and 40.6% vs. 23.7% following NANB hepatitis. However data were statistically significant only as regard as differences between ALT (p less than or equal to 0.05, B-H; p less than or equal to 0.01, NANB-H) and IgM in the group of B hepatitis only (p less than or equal to 0.05) Differences between elongation of course were also significant in both types of hepatitis (p less than or equal to 0.01). Pathogenetic aspects such as depressed cellular immunity and hepatic disorders due to thalassaemia, which may explain the higher incidence of hepatitis and the tendency of evolution into chronicity, are discussed.