Nocardiosis has been increasingly recognized as a serious infection among persons who otherwise appear healthy and among those with underlying chronic disease, neoplasms, and immunosuppression. Nocardial infection as a complication of AIDS has been reported infrequently. Six patients with AIDS and nocardiosis were identified at one New York City hospital from January 1980 through March 1989. Sites of nocardial infection in these patients included the lungs, brain, esophagus, and suprarenal and paraspinal masses. Mycobacteria, fungi, viruses, and bacteria other than Nocardia species caused concomitant infections in three patients. Three patients died of nocardiosis. Because of such factors as the growth properties of Nocardia species, the presence of other organisms, the common use of sulfonamides for treatment of patients with AIDS, and a low index of suspicion among physicians, the incidence of nocardiosis as a complication of AIDS may possibly be underreported. Early recognition of nocardial infection may lead to an improved prognosis.