During the period 1981-2000, we diagnosed eight cases of HIV-Nocardia co-infection (0.38% of AIDS cases). Six were males, and the mean age was 28.6 years. The most common risk factor for HIV infection was intravenous drug abuse. Most patients were severely immunodepressed at the time of diagnosis (mean CD4+ count, 35 cells/ micro L). The clinical forms of nocardiosis seen were pulmonary infection in three, skin or soft tissue infection in three, disseminated in one, and pulmonary colonization in one. Most patients were given sulfonamides, and a clinical response was observed in six of seven treated patients. However, two patients with pulmonary disease died from progressive infection. Although its incidence is very low among AIDS patients, nocardiosis is associated with high morbidity and mortality among HIV-infected individuals.