Klebsiella pneumoniae is the leading cause of liver abscess in diabetic patients in Taiwan. We report the case of a diabetic patient with a history of four episodes of K. pneumoniae liver abscess within 3 years. The patient later developed Streptococcus bovis bacteremia originating from a colon tumor with complications of endocarditis, osteomyelitis, and silent splenic abscess. Occult colon tumor may have played an important role in our case, with recurrent infection arising from colonizers of the gastrointestinal tract. As our case shows, the possible association between occult colon tumor and K. pneumoniae liver abscess in diabetic patients should be surveyed.