The diagnosis of tularemia is very difficult due to rareness of infection and diversity of disease spectrum. Tularemia tends to be not suspected until after the incidental isolation of Francisella tularensis even in highly endemic areas. Tularemic endocarditis is extremely rare, only one case has been reported in adult. Considering importance of blood culture for diagnosing infective endocarditis, tularemic endocarditis may be underestimated by exceedingly low sensitivity of routine blood culture and empirical therapy with gentamicin in infective endocarditis. We recently experienced a first pediatric tularemia case in Korea, presented with infective endocaridits and secondary pneumonia. To our knowledge F. tularemia endocarditis has never been reported in pediatrics. In fact, we had never suspected tularemia until the isolation of F. tularensis. It is noteworthy that the identification of F. tularemia as pathogen of infective endocarditis would have been impossible if blood culture had not been incubated for an extended period. The present case suggests that F. tularensis should be considered in undetermined cases of infective endocarditis, even in non-endemic regions for tularemia. In addition, if endocarditis is suspected, clinicians should request that the blood culture be incubated on enriched media for longer than usual to detect fastidious bacteria like F. tularemia.