Mycobacterium massiliense (M. massiliense) was identified recently as a species that separated from M. abscessus. Unlike M. abscessus, M. massiliense responds well to clarithromycin-based antibiotic treatment. Many cases of M. massiliense infections related to iatrogenic procedures have been reported. We report a case of skin and soft tissue infection by M. massiliense, which was not caused by medical appliances, that was treated successfully using clarithromycin monotherapy for -6 months after initial treatment with empirical antibiotics for 4 weeks.