Predisposing factors (bacteremia, endothelial damage, ...) are important for development of endocarditis in cattle. A dairy cow was referred to Teaching hospital of veterinary faculty. Clinical examination revealed cardiac murmur on auscultation and a chronic abscess on thorax. There was a constant neutrophilia and progressive anemia in cell blood count (CBC). Endocarditis was diagnosed clinically. Because of poor prognosis the cow was slaughtered and vegetative valvular endocanditis accompany by one hydatid cysts on right atrium were found. Actinomyces pyogenes was 1solated from lesions. This is the first report of concurent hydatid cysts and endocarditis in dairy cattle.