Streptococcus agalactiae is known to cause invasive infections in risk groups such as pregnant women, newborns, and immunosuppressed patients but it is uncommon in older children. We describe a case of recurrent infective endocarditis due to S. agalactiae in an 11-year-old boy with Loeys-Dietz syndrome who was successfully treated with long-term antimicrobial therapy for one year.