To clarify the potential diagnostic biomarkers for asbestosis and silicosis, we measured the serum concentrations of KL-6, SP-D, and MMP-2, -7, and -9 in discriminating patients with asbestosis and silicosis from dust-exposed workers (DEWs) without pneumoconiosis and healthy controls (HCs). The gene discussed is SFTPD; the disease is pneumoconiosis.