The hepatitis viruses A through D are prevalent among patients at risk for human immunodeficiency virus (HIV) infection. The courses of hepatitis B, C, and D are modified by HIV infection. With hepatitis B, increased carriage rates, increased viral replication, and milder liver injury are seen. The degree of HIV-induced immunosuppression does not correlate well with liver injury or amount of hepatitis B viral replication. With progression to AIDS, surface antibody titers can decline, resulting in reactivation of latent hepatitis B virus or reinfection with another subtype. Hepatitis B virus may enhance progression to AIDS. Preliminary data suggest that HIV infection can prolong or increase hepatitis C or D viremia and decrease the accuracy of tests for hepatitis C. Interferon may have efficacy against hepatitis C but rarely against hepatitis B in patients who are coinfected with HIV. Zidovudine, ganciclovir, and foscarnet also may be active against these hepatotropic viruses.