Due to the use of vaccines, infections caused by Corynebacterium diphtheriae are now rare. Here we describe a case of bacteremia complicated with pneumonia caused by C. diphtheriae in a 69-year-old male patient. The patient presented at the emergency department with a 2 days history of fever of unknown origin. Subsequent examinations revealed pneumonia and bacteremia. Non-toxigenic C. diphtheriae strains were isolated from blood and sputum. The patient had antimicrobial therapy with good improvement. We highlight the important role of C. diphtheriae in causing bacteremia and pneumonia, and its accurate and timely diagnosis is needed to avoid poor visual outcomes.