Microbacterium oxydans, a coryneform gram-positive bacillus, have been isolated from a wide variety of environmental sources and reported its pathogenic potential with increasing frequency in the last few years. Microbacterium comprises more than 60 species. 16S rRNA sequences in different Microbacterium species are highly conserved and the differences of biochemical characteristics between several species are unclear. As a result, identification of Microbacterium to species level has been difficult in most clinical microbiology laboratories. In this article, we report a case of catheter-related bacteremia caused by M. oxydans that was identified by 16S rRNA sequencing analysis and phenotypic characteristics in patient with diffuse large B-cell lymphoma. (Korean J Clin Microbiol 2010;13:173-177)