Mycobacterium celatum is a recently described nontuberculous mycobacterium. Even though pulmonary or lymphatic infection cases were reported previously in human, the clinical significance of the infection with M. celatum is not yet understood completely. Mast infections with this species occurred in the patients with suppressed cell-mediated immunity such as AIDS, and there are only a few cases of pulmonary infection with M. celatum in immunocompetent adults or infants in the world. In Korea, mycobacterial pulmonary infection is a major problem of respiratory disease but, there has been no pulmonary infection with M. celatum reported. We report, to our knowledge, the first Korean case of pulmonary infection with M. celatum, which was identified by rpoB genomic sequencing.