A case of HIV superinfection observed in an HBsAg/HBeAg-positive male homosexual with chronic persistent hepatitis is described. Soon after the appearance of clinical and serological features of acute HIV infection, a rapid fall to a normal value of ALT was noted with simultaneous recrudescence of HBV replication lasting for several months as detected by an increase of the HBV-DNA concentration in the serum. Our observations suggest that the reduction of hepatocyte necrosis and the increase in HBV replication were a consequence of impaired T cell function during acute HIV infection.