The incidence of opportunistic fungal infection, mucormycosis associated with high mortality rate is steadily increasing. Pulmonary mucormycosis though rare, it relatively affects individuals with diabetes mellitus and other immunosuppressive conditions. The present study reports on case of pulmonary mucormycosis caused by Rhizopus microsporus. Sputum sample was collected from a 47-year-old male with diagnosed with tuberculosis with spontaneous left sided pneumothorax and diabetes mellitus. The positive fungal culture was characterized by phenotypic and genotypic methods and antifungal susceptibility of the isolate was tested against azoles and amphotericin B. The etiological agent was identified as R. microsporus based on phenotypic features and molecular sequencing of ITS. The isolate was susceptible to all the tested antifungal and the patient responded well to Amphotericin B with strict glycemic control and combination of anti-infective therapy. Though pulmonary mucormycosis is relatively rare; it share its clinical picture with pulmonary tuberculosis and aspergillosis, hence clinical suspicion for mucormycosis in susceptible high risk patients is warranted for early diagnosis and appropriate therapy.