A 75-year-old woman was admitted to our hospital with a 3-month history of fever. Of note, she had a bioprosthetic mitral valve replacement 1 year prior to admission. Streptococcus bovis was isolated from three sets of blood cultures. An echocardiogram showed a flickering mass attached to the bioprosthesis. Her blood culture became sterile by the fourth day of ceftriaxone therapy. In spite of the absence of gastrointestinal symptoms, screening colonoscopy revealed an invasive colonic adenocarcinoma. The association linking S. bovis endocarditis and colonic tumours is well recognised. However, despite early reports of this association by Klein et al in 1979, a large number of practising physicians remain unaware of this phenomenon. This lack of awareness results in lost opportunities for early diagnosis and, consequently, improved outcome in such patients. Our report emphasises this association in an area with a low incidence of S. bovis endocarditis.