Six species of oak are commonly found in Korean forests growing together with evergreen pines. Korean oak forests have recently been attacked by ambrosial fungi of the genus Raffaelea and by many other fungal species that are vectored by the beetle Platypus koryoensis. We investigated a full list of the diverse decay fungi as a first step to better understand the association between these fungi and oak trees, as well as considering effective management methods for oak forests in Korea. Through examination of specimens deposited in the Seoul National University Fungus Collection (SFC) and the National Institute of Biological Resources (NIBR), 523 decay fungi (104 species) associated with oak trees were identified and a full list is provided.