43 subjects, affected by chronic aggressive hepatitis (CAH) have been divided into two groups according to the presence of HBAg. No statistically significant differences between the two groups have been provided. The two classes of subjects (HBAg + and -) were also divided into the already treated (with immunosuppressive drugs) and untreated to investigate the eventual differences existing between the two classes. The results of this division was that previously treated subjects present a lower total bilirubin (P less than 0.05) in respect to those that were not treated previously. The results of all the other comparisons carried out and the tested correlations were negligible. In conclusion, bearing in mind the inadequate methods used up to now to research the HBAg, the transversal studies show that CAH patients are both affected by the same syndrome, whether the HBAg is positive or negative. However, it is probable that it is not the carrier state of HBAg which enables the liver disease evolution but the liver disease itself enables the cellular immunity disorders that often appear in the course of CAH.