As one of the most lethal infections caused by fungi, pulmonary mucormycosis usually affects patients who are immunocompromised. Isolated pulmonary mucormycosis in immunocompetent patients is very rare.This report describes a 65-year-old immunocompetent man, who was first treated with antibiotics after being diagnosed with a lung infection, then after the lack of response to treatment, he was diagnosed with mucormycosis in further investigations. Finally, the patient died due to a lack of response to treatment. Despite its rarity, it is important to consider other differential diagnoses such as pulmonary mucormycosis if the pneumonic process does not respond to medical treatment.