A twenty nine year old male homosexual presented with malaise, weight loss, fever and profuse sweating. An ill defined abdominal mass was found during physical examination in the right lower quadrant and chest X rays disclosed a pleural effusion. HIV antibodies and hepatitis B surface antigen were positive and immunological parameters were altered. Light and electron microscopic examination of operative biopsies of the abdominal mass revealed the presence of Histoplasma capsulatum. Treatment with Amphotericin B was started with a favorable response and the patient was discharged. He was readmitted with a septic shock and died. Necropsy showed pulmonary histoplasmosis. This is the first case of disseminated histoplasmosis in a patient with AIDS described in Chile.