Clinical and epidemiological characteristics of Streptococcus bovis endocarditis were prospectively studied among 199 patients with definite endocarditis. Thirty patients (15.1%) had S. bovis endocarditis. Compared with patients with non-S. bovis endocarditis, these 30 patients were older (mean age, 58.6+/-12.4 years vs. 46.0+/-17.0 years; P<.001) and had higher rates of bivalvular involvement (43.3% vs. 7.7%; P<.001), embolism (73.3% vs. 40.2%; P=.002), and diskitis (23.3% vs. 0.6% P<.001). In patients with S. bovis biotype I (S. bovis I) endocarditis, advanced liver disease was present in 56.7%, compared with 15.3% of patients with non-S. bovis endocarditis (P<.001), and colonic adenoma was present in 46.7%. The in-hospital mortality rate (16.7%) was correlated with delayed diagnosis and advanced liver diseases. In our city, S. bovis I endocarditis is frequently correlated with liver diseases; diskitis may be the first sign of the disease.