An 81-year-old man presented with severe back pain. Magnetic resonance imaging detected L5/S discitis without signs of epidural abscess. Punctures of the disc revealed that the causative organism was Gemella morbillorum (G. morbillorum), which is part of the normal flora of the oral cavity and an uncommon causative pathogen of spondylodiscitis. The E-test method was useful for rapid susceptibility testing. Intravenous penicillin G treatment was effective, and the patient recovered without surgery.