Although viral hepatitis infection is known to be associated with aplastic anemia, a causal link between viral hepatitis and aplastic anemia has not been convincingly demonstrated. A case of hepatitis B-associated severe aplastic anemia is described which only partially responded to conventional immunosuppressive treatment but went into complete clinical remission after clearance of the hepatitis B virus. Disappearance of the hepatitis B virus occurred during lamivudine treatment and coincided with immune activation secondary to discontinuation of immunosuppressive therapy. This case was somewhat atypical in that a history of acute hepatitis preceding the aplastic anemia was absent. The observation made in this case report supports a cause-effect relationship between hepatitis B virus infection and aplastic anemia.