This case study describes three diabetic patients in Sri Lanka who developed a serious lung infection caused by a fungus called mucormycosis. The infection caused cavities in the lungs and symptoms like fever, cough, and weight loss. Two patients recovered with antifungal medication (amphotericin B) and surgery, while one patient sadly died despite receiving treatment. The study emphasizes that doctors should consider this infection in diabetic patients with unusual lung symptoms to catch it early.