Microbacterium oleivorans is a gram-positive, coryneform rod bacterium. The pathogenic potential of the Microbacterium species has recently been reported to be increasing. Microbacterium comprises approximately 50 species. The differences in regards to the biochemical characteristics of Microbacterium species are unclear, and is why molecular investigations (e.g., using 16S rRNA gene sequencing) are the best method to identify the species. We report a case of bacteremia that was caused by Microbacterium oleivorans in a 4-year-old boy, who had no specific medical history. This represents the first report of M. oleivorans bacteremia in Korea. (Korean J Clin Microbiol 2012;15:110-113)