South Korea has been free from endemic malaria by P. vivax since the mid-1980s, but malaria infections, including military outbreak in 1995, have been increasing steadily in the soldiers serving near the western part of Demilitarized Zone(DMZ) since its first resurgence in 1993. We experinced 8 cases of delayed onset P. vivax malaria in young men who had never been abroad and had no history of blood transfusion or parenteral use of drug. All the patients had served near the western part of DMZ during their military life. They were admitted to Yeungnam University hospital due to cyclic fever with chills and the clinical symptoms were developed 2 months to 11months after discharge from military service. Peripheral blood smears showed typical ring forms and trophozoites of P. vivax in red blood cell. Patients were treated with hydroxychloroquine and primaquine showing rapid clinical and hematologic responses in all cases, but 2 cases were relapsed later. We presumed that theses cases were delayed onset of P. vivax infection resulted from the recent outbreak in the western part of DMZ, in 1995. Therefore, we reported theses cases to emphasize the need of active surveillance and prevention.