Microbacterium species are gram positive coryneforms generally considered as a contaminant when identified in gram stain of blood culture, especially when time-to-positivity is longer than 48 h. We encountered a case of infective endocarditis associated with Microbacterium maritypicum bacteremia, which became positive after 48 h of incubation in three out of four bottles. The antimicrobial management is controversial as vancomycin is generally assumed to cover most gram positive bacilli, but our susceptibility result demonstrated minimum inhibitory concentration of 4 μg/mL of vancomycin, indicating non-susceptibility. To the best of our knowledge, this is the first case report of infective endocarditis associated with Microbacterium maritypicum.