Mycobacterium gordonae is a slow growing scotochromogenic acid fast bacillus (Runyon group II) with specific cultural and biochemical characteristics. It is a contaminant of water, soil, and raw milk and is usually considered to be saprophytic and non-pathogenic in man. We have recently seen two cases of pulmonary disease that may have been due to M gordonae, and we now report these and review our recent experience of this organism.