Abstract: We reviewed the data of 38 neonates who died of respiratory failure. Paraffin sections of the autopsy lung samples were examined with HE staining or immunolabeling for CD34, CD68 and CK to observe the development of the pulmonary vessels and detect potential pulmonary vascular diseases (PVDs). Five cases were identified to have PVDs, including pulmonary hypertensive vascular remodeling in 3 cases and alveolar capillary dysplasia in 2 cases. The result indicated that PVD was one of the important reasons for respiratory failure in these neonates.