Histoplasmosis is a serious opportunistic infection in patients with AIDS. Fluconazole is a triazole antifungal agent that has been used successfully in the treatment of experimental histoplasmosis in animals, but has not been completely evaluated in patients for this use. It has been approved by the Food and Drug Administration for certain other fungal infections. Nevertheless, physicians are prescribing it to their patients with histoplasmosis. This is a pilot study to examine the role of fluconazole for treating histoplasmosis in AIDS patients.