Abstract: Olive flounder (Paralichthys olivaceus) is the most popular consumption fish in South Korea. Korean consumes flounder as sashimi, spicy soup, stew and cutlet. Due to its popularity; Korean considers Olive flounder as the nation’s raw fish. Despite advanced aquaculture technique, modern facilities and massive production, fingerling size grading and abnormal sorting are conducted by traditional method. This study was conducted by observation. A group of 5 to 6 person worked meticulously to sort out abnormal fingerling and juvenile. Sorting is based on physical traits such as the shape and structure of head, jaw, operculum, fin, body; body coloration, pigmentation and length. Due to the exclusiveness and technicality of this profession, information and standard in grading and sorting has been lacking. This research provides the information about sorting criteria of Olive flounder juvenile and detail description of physical abnormalities being sorted out.