A 19-year-old male patient was diagnosed with S. sanguinis brain abscess of unknown etiopathology as a complication of subclinical endocarditis. While viridans streptococci are implicated in dental seeding to the heart, S. sanguinis brain abscesses are rare. Six previous cases of S. sanguinis brain abscess in the literature reported dental procedures and maxillofacial trauma. In our patient, there was no obvious source of infective endocarditis preceding the development of brain abscess. This demonstrates the importance of prompt diagnosis and initiation of antimicrobial therapy given the potential for long-term sequelae such as focal deficits and seizures.