The use of highly active antiretroviral therapy (HAART) has extended the healthy lifespan of patients infected with human immunodeficiency virus (HIV); deaths among people with AIDS declined for the first time in 1996, after the institution of this therapeutic approach. As the life expectancy of HIV-infected patients increases, greater attention will need to be focused on the recognition and management of potentially severe concurrent illnesses that may increase their mid- to long-range morbidity and mortality. The incidence of infection by hepatitis C virus (HCV) is increased among patients with HIV disease, reflecting shared epidemiological risks. HCV not only may have an impact on the health status of HIV-infected patients but also may decrease their quality of life and increase their health care costs. Although clinicians have been reluctant to treat viral hepatitis C in the HIV-infected population, this therapeutic nihilism is unwarranted. The majority of studies have concluded that treatment of hepatitis C in HIV-infected patients results in an initial efficacy and long-term response similar to those in the HIV-seronegative population. Furthermore, treatment of HCV infection in HCV/HIV-coinfected patients may improve tolerance for antiretroviral medications. Physicians caring for patients with HIV infection require up-to-date information to make rational decisions regarding HCV coinfection to ensure that morbidity and mortality are minimized and that quality of life and medical care costs are optimized.