Left atrial thrombosis in the absence of rheumatic heart disease and atrial fibrillation is rare. After orthotropic heart transplantation, despite of an uneventful post-operative course, sinus rhythm and normal contractility of the heart, large thrombi could be found several months following. Transplantation, because the enlarged atria may promote atrial thrombosis. Operative technique is proposed as one of the main factors that can contribute to left atrial thrombosis. TEE is the best method for detection of left atrial thrombosis. Usual treatment of thrombosis is surgical thrombectomy But we report medical treatment of large left atrial thrombus with 3 years uneventful follow up.