Four cases of human infection by Echinochasmus japonicus (Trematoda; Echinostomatidae) were proven by the recovery of adult worms after a treatment with praziquantel (10 mg/kg in single dose) and purgation in February 1984 in Korea. The patients were 3 middle-aged men and 1 elderly woman residing in a riverside village of Kangjin-gun ( Tamjin river), Jeonranam-do, an ever-known endemic area of metagonimiasis. The treatment revealed numerous M. yokogawai worms together with 1-43 (total 54 ) specimens of E. japonicus and/or a few number of other kinds of trematodes or cestodes. The patients had gastrointestinal troubles such as indigestion and abdominal discomfort, probably due to these fluke infections. They have been eating some raw flesh of fresh water fishes such as cyprinoid ones or sweetfish caught from the river. This is the first record of human E. japonicus infection in the literature.