BACKGROUND: Screening of donor blood for malaria has not been activated in Korea yet in spite of the recent resurgence of tertian malaria among Korean army soldiers in Delimited Militarized Zone areas. Prospective donors (travelers, immigrants, refugees, citizens or residents) following a visit to or coming from an endemic area who have had malaria or taken antimalarial prophylaxis should be deferred for 3 years after cessation of therapy or after departure from malarial area. We studied the risk of the transmission of malaria, especially through army blood donation which comprised up to 57.8% of whole blood donation in Korea. METHODS: The data were collected by personal interview and review of donation records of Korea Red Cross Center and medical records from 174 army soldiers with malaria who admitted to Army Hospital from May 1995 to October 1996. We analyzed the time interval between onset of illness and blood donation, and geographic distribution of the patients. RESULTS: About 70.7% (123/174) of the patients donated blood before the onset of illness, and the interval between blood donation and onset of illness ranged from 2 days to 2,750 days (mean 377, standard deviation 488). Patients who donated blood within 3 years before onset of illness were 87.8%(n=108) of the total blood donation. All donation (n=18) after treatment were within 3 years from 46 days to 342 days (mean 138, standard deviation 80.7). The frequent of blood donations were from the prevalent areas of malaria such as Pajoo City (40%), Younchon Kun (29%), Cholwon Kun (15.5%) and others(15.5%). CONCLUSION: We showed that donated army blood a risk of malaria transmission. Therefore the blood bank needs to set strict guidelines for blood donation especially from Korean army soldiers to control malaria transmission.