Histoplasmosis, also referred to as Darling's disease, is mainly caused by the thermally dimorphic fungus Histoplasma capsulatum. It is usually contracted by inhaling fungal spores found in soil contaminated with bat or bird droppings, often during activities like cave exploration. Although endemic in certain regions of India, such as the eastern part, and sporadically in southern and northern states, histoplasmosis can manifest with varied clinical presentations, ranging from asymptomatic to severe disseminated disease affecting multiple organs. Adrenal involvement, though relatively uncommon, can lead to adrenal insufficiency, especially in immunocompetent individuals, with bilateral adrenal enlargement being a characteristic feature in imaging studies. This report discusses the case of a 51-year-old farmer from Haryana, India, who was diagnosed with progressive disseminated histoplasmosis (PDH) resulting in primary adrenal insufficiency. Although tuberculosis or malignancy was initially suspected, imaging studies and biopsy results confirmed histoplasmosis as the root cause. This case emphasizes the necessity of including histoplasmosis in the differential diagnosis of primary adrenal insufficiency, especially in endemic areas, and highlights the importance of early detection and appropriate management of this potentially life-threatening disease.