Malaria is estimated to have a worldwide incidence of more than 100 million clinical cases and approximately 1 million deaths per year. Korea, although previously known as an endemic area of tertian malaria (Plasmodium vivax), has been considered free from malaria as there had been no report on indigenous cases since 1984. Recently, however, we experienced an indigenous case of P. vivax infection in a young man who had never been abroad. The patient was a 23-year-old Korean soldier with 18-day history of recurrent fever and chill lasting 4 to 8 hours on alternative days since mid-July 1993. He had lived in Changwon, Kyongsangnam-do, before entering barracks located in Paju-gun, Kyonggi-do on June 1992, and had never been out of Korea. He had no history of blood transfusion nor parenteral use of drugs. The peripheral blood smears showed typical ring forms, trophozoites, and gametocytes of P. vivax, in addition to mild anemia and thrombocytopenia. After confirmation of the diagnosis, he was treated with hydroxychloroquine and primaquine. Follow-up blood smears no more revealed malaria parasites. It is not certain whether the present case is due to a resurgence of indigenous malaria or a secondary infection from introduced malaria. Whichever the source of infection the domestic occurrence of malaria cycle in Korea should be a warning sign in public health point of view.