Pulmonary hypertension occurs with increased frequency among patients with human immunodeficiency virus (HIV) infection. Although the pathogenesis of HIV-associated pulmonary hypertension remains unknown, it appears to occur independently of other risk factors associated with pulmonary vasculopathy, such as chronic hepatitis C infection and intravenous drug use. Signs and symptoms are typical of those immunocompetent patients with primary pulmonary hypertension, but because many HIV-infected patients are receiving intensive medical supervision, the diagnosis of pulmonary hypertension is often made at an earlier stage. Acute responses to epoprostenol are similar to those among non-HIV-infected individuals, but the benefits of long-term, intravenous treatment with epoprostenol in HIV-infected patients is unknown. Future investigations should define the true incidence of pulmonary hypertension and the long-term effects of epoprostenol on survival among HIV-infected individuals. Physicians should be alert to possible pulmonary hypertension in persons infected with HIV.