Infective endocarditis is an acute or a subacute inflammatory infection of the endocardium caused by bacterial, viral or fungal microorganisms. Despite significant improvements in the diagnosis and treatment, it is still associated with a poor prognosis and a high mortality rate. Viridans streptococci are one of the most common causative microorganisms of bacterial endocarditis. Streptococcus mutans, a member of this group and is usually associated with dental carries. Although it is expected to be more frequently associated with endocarditis, has only rarely been reported. This is most likely to be due to some identification problems. We herein report a case of infective endocarditis due to Streptococcus mutans following tooth extraction with no history of heart disease.