Histoplasmosis is a fungal infection caused by Histoplasma capsulatum. In the normal individual, both disseminated histoplasmosis and symptomatic adrenal histoplasmosis are rare. Herein, we describe the case of a 50-year-old gentleman residing in western Sudan who presented with a 7-month history of generalized body weakness, easy fatigue, and frequent attacks of vomiting and diarrhea. Physical examination and laboratory investigations confirmed the diagnosis of Addison's disease due to Histoplasma capsulatum var duboisii infection of the adrenal glands. He was treated with intravenous hydrocortisone, followed by oral prednisolone and itraconazole.