METHODS Symptomatic pulmonary aspergillosis has rarely been reported in patients with the acquired immunodeficiency syndrome (AIDS). We describe the predisposing factors, the clinical and radiologic features, and the therapeutic outcomes in 13 patients with pulmonary aspergillosis, all of whom had human immunodeficiency virus (HIV) infection and 12 of whom had AIDS. RESULTS Pulmonary aspergillosis was detected a median of 25 months after the diagnosis of AIDS, usually following corticosteroid use, neutropenia, pneumonia due to other pathogens, marijuana smoking, or the use of broad-spectrum antibiotics. Two major patterns of disease were observed: invasive aspergillosis (in 10 patients) and obstructing bronchial aspergillosis (in 3). Cough and fever, the most common symptoms, tended to be insidious in onset in patients with invasive disease (median duration, 1.3 months before diagnosis). Breathlessness, cough, and chest pain predominated in the three patients with obstructing bronchial aspergillosis, who coughed up fungal casts. Radiologic patterns included upper-lobe cavitary disease (sometimes mistaken for tuberculosis), nodules, pleural-based lesions, and diffuse infiltrates, usually of the lower lobe. Transbronchial biopsies were usually negative, but positive cultures were obtained from bronchoalveolar-lavage fluid or percutaneous aspirates. Dissemination to other organs occurred in at least two patients, and direct invasion of extrapulmonary sites was seen in two others. The results of treatment with amphotericin B, itraconazole, or both were variable. Ten of the patients died a median of 3 months after the diagnosis (range, 0 to 12 months). CONCLUSIONS Pulmonary aspergillosis is a possible late complication of AIDS; if diagnosed early, it may be treated successfully.