Hydatid cyst is a parasitic disease caused by Echinococcus granulosus. It is endemic in Asia, Africa, South America, and the Mediterranean region including Turkey. Cardiac involvement is rare. Surgery is the definitive treatment of cardiac hydatid cysts; however, to avoid recurrence after surgery, medical therapy should be also continued. Left ventricular free wall is the most common location, followed by the right ventricle and interventricular septum. Involvement of mitral valve is extremely rare. Herein, we present a case of hydatid cyst with myocardial involvement leading to severe mitral valve regurgitation which was successfully treated with surgery.