INTRODUCTION: Microbacterium species are gram-positive, non-fermentative, yellow-pigmented rods commonly found in animals and various environmental sources. Herein is reported the first case of a fatal bloodstream infection associated with mitral endocarditis caused by Microbacterium paraoxydans in a human patient. METHODS: A 64-year-old man without significant infectious risk factors, except for rheumatoid spondylarthritis treatment, developed severe chest pain, paralysis of the left leg, respiratory distress, and high fever. Diagnostic investigations revealed ischemic stroke and mitral insufficiency. Despite valve replacement surgery and antibiotic treatment, the patient's condition deteriorated, resulting in valve disinsertion, pneumopathy, and death. RESULTS: Blood cultures taken later confirmed the presence of Microbacterium sp., identified as M. paraoxydans by 16S rDNA gene sequencing. CONCLUSION: This case highlights the importance of using sequencing for accurate identification of Microbacterium species. This report emphasizes the need for research and surveillance to understand the clinical characteristics, treatment strategies, and impact of Microbacterium infections in humans.