Japanese pine sawyer beetle (Monochamus alternatus) is an economically important pest in coniferous trees. Ophiostoma ips was isolated from the beetle and identified based on analysis of morphological properties and the ${eta}$-tubulin gene sequence. The fungus easily produced perithecia with a long neck on malt extract agar and its ascospores were rectangular shaped. This is first report of Ophiostoma species associated with the pinewood nematode vector beetle in Korea.