Abstract Background: Group B Streptococcus (GBS) is the most common pathogen responsible for perinatal bacterial infections. While the early-onset (EO) disease typically presents with pneumonia or sepsis, bacteremia and meningitis represent usual presentation of late-onset (LO) disease. Other clinical manifestations are relatively rare. Highlights: Here we describe an infant with a brain abscess due to a late-onset, GBS serotype I infection. A previously healthy 42-day-old baby presented with insufficient sucking, vomiting, irritability and fever. Cerebrospinal fluid (CSF) analysis, cultures and magnetic resonance imaging (MRI) confirmed the diagnosis of type I group B streptococcal meningitis with brain abscess. The patient made full recovery after a 4-week course of treatment with meropemen and ampicillin. No surgical drainage of the abscess was required. At a 3-year follow-up, the patient had a normal global development with no neurological sequelae. Conclusions: Brain abscess due to GBS late-onset infection is very rarely described. Furthermore, type I GBS is infrequent in late-onset disease. Therapeutic choices in these neonates are challenging because of lack of standards. A long-term follow-up of late-onset disease survivors is mandatory to exclude late developmental impairment.