Endemic histoplasmosis occurs uncommonly in Australia and has not previously been reported in the tropical Northern Territory, nor in Aboriginal Australian patients. We report one suspected and one confirmed case of severe disseminated histoplasmosis in Aboriginal Australians from the Northern Territory. Underlying illness included chronic cardiac disease and Type 1 diabetes mellitus, respectively, and neither patient was infected with HIV. The clinical presentations resembled malignancy. Diagnosis of histoplasmosis was made on the basis of bowel histology in Case 1, demonstrating characteristic yeasts, and lymph node histology and culture in Case 2. Histoplasmosis should be considered in relevant clinical situations, even in HIV-negative patients who have not left Australia.