The study presents the introduction of the DDT (Dichloro-Diphenyl-Trichloroethane) during the third phase of the Greek antimalarial fight, after the end of the Second World War. The material is derived from the archive of United Nations Relief and Rehabilitation Administration (UNRRA), the personal archive of Colonel Daniel Wright, head of the UNRRA Department of Malaria in Greece, and the Reports of the Department of Malaria of National School of Public Health (Ministry of Health Archive, General State Archives). At the end of the Second World War, malaria was a serious hygienic problem in Greece. According to the international organizations' data, 87% of the country's territory had malaria, while the patients amounted to three million. According to the Greek data, the malaria epidemics mainly detected Plasmodium falciparum, while in the endemic areas P. vivax and P. malariae. In addition, Greece had the particularity of the existence of mosquitoes Anopheles superpictus whose biological cycle extended the periods of epidemic waves until October. The advent of UNRRA and the introduction of DDT changed the form of antimalarial fight with amazing results. Despite the problems and the scientific controversies that had arisen, it is timeless the lesson of the proper epidemiological control and constant vigilance for the preservation of public health.