We describe a human immunodeficiency virus (HIV)-infected patient with chronic active hepatitis B. The patient presented with acute clinical hepatitis during highly active antiretroviral therapy concomitant with immunovirological improvement of HIV infection. The hepatitis resolved within a few weeks despite the pursuit of antiretroviral drugs. Hepatitis B tests, which remained unchanged after two cycles of interferon alfa therapy and continuous administration of lamivudine, were improved with the clearance of hepatitis B virus (HBV) early antigen (HBeAg), the detection of antibody to HBV early antigen (HBeAb) and the undetectability of serum HBV DNA. Several months after this episode, HBV and HIV tests are still controlled.