Often dismissed as contaminants in blood cultures, Corynebacterium species can also cause infective endocarditis, a severe condition. We report an unusual case of Corynebacterium propinquum endocarditis in a non-immunocompromised individual on a native valve. Conflicting clinical and microbiological data led to 16S ribosomal sequencing to confirm the causative agent. Our case illustrates C. propinquum as a cause of infective endocarditis, and it demonstrates the utility of ancillary molecular diagnostic techniques to identify etiologic agents in difficult cases of infective endocarditis. C. propinquum should be recognized as a potential cause of infective endocarditis even on a native valve.  Kulcsszavak: infective endocarditis, Corynebacterium propinquum, 16S ribosomal sequencing