From an investigation into the distribution and symptomatology of Clonorchiasis sinensis at Mizushima, the southern part of Kurashiki City, the following results have been obtained. 1) The majority of cases occurred in adult Koreans, and only few cases in Japanese. 2) The vectors concerned in this area are mainly Carassius auratus and Cyprinus carpio. 3) Serious cases were found very often.