The prolonged survival of profoundly immunocompromised patients with AIDS has contributed to the increasing recognition of aspergillus infections as an emerging problem. Nevertheless, many of these infections continue to be diagnosed only at autopsy. In this article we review details of 293 reported cases. Invasive aspergillosis occurs in advanced AIDS and most commonly affects the lungs, although brain involvement has also been frequently reported. The diagnosis is often difficult to make while the patient is alive, although examination of specimens obtained via bronchoalveolar lavage, percutaneous needle aspiration, or biopsy is often successful. Biopsy of the affected organ along with histologic examination and culture may be necessary for diagnosis. The dismal prognosis of invasive aspergillosis in patients with AIDS can be improved only with earlier diagnosis of disease and the availability of more-effective antifungal regimens.