We describe the first case, to our knowledge, of Mycobacterium brisbanense species nova with the type strain W6743T (= ATCC 49938T = DSM 44680T) isolated from the lungs of a man with a 6-month history of productive cough and intermittent fever presenting with acute hypoglycemia. A CT scan of the thorax revealed multiple small nodules and consolidation over both lungs with cavitation. Sputum culture repeatedly grew M brisbanense species nova, a novel species never before isolated in Malaysia. The case met the American Thoracic Society criteria for the diagnosis of nontuberculous mycobacterial infection. There was dramatic clinical and radiologic response to treatment with an empirical combination of rifampicin, ethambutol, and levofloxacin and subsequently clarithromycin and levofloxacin once sensitivity was known. This report is the first, to our knowledge, of the pathogen isolated in a patient with chronic cavitary lung infection since it was first identified from an antral sinus in Brisbane, Queensland, Australia, and the first time it is isolated from a human subject in Malaysia.