Streptococcus milleri Goup Bacteria(SMG) comprise three species, Streptococcus anginosus, Streptococcus intermedius, Streptococcus constellatus. Although they are commensal organism, they can be pathogenic. SMG can be aggressive pathogen in the head and neck with a propensity for abscess formation and local extension of the infection. SMG is culturally and biochemically variable, which makes it hard for the clinicians to recognize it. Hence, it seems that this organism has been relatively neglected. Most of the Lancefield F streptococci are SMG. We report one patient who had Group F streptococcal bacteremia and subdural abscess. According to his medical history, he was diagnosed as membranoproliperative glomerulonephritis three years ago. He complained headache although he was treated by appropiate antibiotics. Brain CT was used as a tool to identify the brain abscess. He had surgical drainage and was treated with IV antibiotics postoperatively.