Occurrence of the oak wilt disease (Raffaelea sp.) was confirmed in 2004 for the first time in Korea. By using pictorial keys, morphological characteristics of Platypus koryoensis (Murayama), a vector for this disease in Korea, was compared to Platypus quercivorus (Murayama), a vector of oak wilt in Japan. Additionally, suggestions were made for the future research of the vector of oak wilt disease in the northeastern Asia.