Streptococcus agalactiae is well known to be a potential etiology of bacterial meningitis in neonates. Invasive S. agalactiae has been also reported in nonpregnant adults. Among adults, the incidence of invasive group B Streptococcus (GBS) has been increasing 2-4 times in the past 2 decades. Chronic medical disease was suspected to increase the susceptibility for invasive GBS, especially diabetes mellitus. There was only one case reported to have GBS meningitis from acute otitis media infection in otherwise healthy individual. Hereby, we are reporting the second invasive GBS meningitis from acute otitis media infection with mastoiditis.