Bacillus popilliae, a fastidious, aerobic, gram-positive, spore-forming bacillus, has never been reported as a pathogen in human infectious diseases. We report the first case of a human infected by the pathogen B. popilliae, which presented as endocarditis involving the bicuspid aortic valve and complicated with prolonged (> 30 days; to our knowledge, the longest in the literature) complete heart block. Although surgery may be warranted by previous reports, the patient was successfully managed by medical treatment instead, because of the absence of evidence from various approaches that support the existence of perivalvular extension of infection.