A 65 year old woman with chronic eosinophilic pneumonia was transferred to our hospital with acute dyspnoea. Physical examinations revealed signs of congestive heart failure. Blood analysis revealed an increase in eosinophil counts (1547/mm3). Transthoracic echocardiography showed large masses in the left ventricular apex extending to the posterior mitral leaflet with normal ventricular size and function (panel A). The motion of the posterior mitral leaflet was restricted and severe mitral regurgitation was noted (panel B). Mild tricuspid regurgitation was found and estimated right ventricular systolic pressure was 80 mm Hg. Enhanced computed tomography and magnetic resonance imaging of the heart identified the masses as mural thrombi, making the diagnosis of Löffler’s endomyocarditis. She was treated with steroids, diuretics, and anticoagulation resulting in resolution of symptoms. Repeated echocardiography one month after showed decreased apical thrombi (panel C), but severe mitral regurgitation still existed.