Pulmonary involvement in vascular Behçet's disease (BD) (VBD) is a serious manifestation. Among the pulmonary manifestations, pulmonary embolism is considered a rare manifestation because deep vein thrombosis (DVT) has been thought to detach from the vessel wall, whereas pulmonary thrombus has been suggested to result from in situ pulmonary arteritis.In this case report, we present histopathological evidence of pulmonary embolism derived from DVT in an autopsy case of VBD. This observation emphasises that DVT causes pulmonary embolism in BD, indicating that anticoagulants are required for its prevention.