The present report describes a case of Bartonella henselae endocarditis affecting an adolescent with congenital heart disease. A teenager from Eastern Europe was referred to for surgical treatment of aortic endocarditis. She admitted close contact with cats. Blood culture was negative. Diagnosis of B henselae was established on direct PCR amplification and 16SrRNA gene sequencing of the aortic valve tissue and confirmed after 4 weeks by valve culture isolate. The patient underwent extended root replacement (the Ross-Konno operation) with a favourable outcome.