Background and Aim: Mucormycosis represents a group of life threatening infections caused by fungi of the order mucorales. Mucormycosis results in higher rates of morbidity and mortality than many other infections. A high index of suspicion and considering risky factors are critical for diagnosis and early initiation of therapy is necessary to optimize outcomes. In this paper, we report a woman with pulmonary mucormycosis. Case Report: A 47-year old woman with a history of uncontrolled diabetes presented with cough, hemoptysis, dyspnea and dysphagia from 3 weeks ago. On physical examination, course crackles, generalized wheezing and stridor were found along with fever. Laboratory testing demonstrated a high-titer ESR, CRP3+ and leukocytosis. The ENT examination revealed a mild erythema of the vocal cords. An initial chest-x-ray was compatible with a pulmonary infiltration in the right middle lobe. Ct-scan of the sinuses was unremarkable. Bronchoscopy findings and lung biopsy was consistent fibrinoleukocytic exudates with extensive necrosis and broad hyphae and was reported fungal infection in favor of mucormycosis. She was eventually treated with amphotericin B. Ethical Considerations: This study with research ethics code IR.ARAKMU.REC.1398.48 has been approved by research ethics committee at Arak University of Medical Sciences.Conclusion: Mucormycosis has high mortality in diabetic patients and has even higher rates in uncontrolled diabetics. Therefore, due to underestimation and undertreatment of the condition, mucormycosis must be considered in diabetics underestimate pneumonia.