An 18-year-old man presented with a history of oral sores and presence of high fever, scrotal ulcerations and haemoptysis. Multiple mural cardiac masses were present in the right atrium, right ventricle and left ventricle. Furthermore, pulmonary vasculitis with aneurysm formation and venous thrombosis involving the superior sagittal sinus and right transverse sinus were found, and the diagnosis was made of (incomplete) Behçet's disease. While receiving anticoagulation and later, treatment with prednisone and cyclophosphamide, the cardiac thrombi gradually disappeared. We stress the importance of early echocardiography to evaluate cardiac abnormalities in Behçet's disease.