Churg-Strauss syndrome is a rare syndrome that is characterized by hypereosinophilic systemic necrotizing vasculitis affecting small- to medium-sized arteries and veins. The manifestations of multiple tracheobronchial mucosal lesion and thrombus of left ventricle are rarely reported in Churg-Strauss syndrome. We report a case of Churg-Strauss syndrome with diffuse tracheobronchial mucosal lesions in a 52-year-old man who developed a left ventricular thrombus after discontinuation of treatment. Bronchial asthma, rhinosinusitis, peripheral eosinophilia, p-ANCA positive, eosinophilic lung infiltration, vasculitis led to a diagnosis of Churg-Strauss syndrome. On bronchoscopic evaluation, diffuse necrotizing mucosal lesions were observed on tracheobronchial tree. With methylprednisolone (125 mg/day), his asthmatic symptoms were well-controlled and eosinophil count and eosinophil cationic protein concentration in peripheral blood maintained in normal ranges over a 20 month period, but he was lost to follow-up. After 12 months from discontinuation of treatment he readmitted with relapsed Churg-Strauss syndrome with left ventricular thrombus. The thrombus gradually disappeared after prednisolone (1 mg/kg/day) and warfarin treatment.