The results of adult mosquitoes collection at Uijeongbu-si, Dongducheon-si in Gyeonggi-do where malaria outbreak occur in Korea are presented. Light traps collection were operated for adult collection from April to October, 2001. Among the total 12 species comprising 4 genera, 4 species in Anopheles, 3 species in Aedes, 1 species in Armigeres and 4 species in Culex were identified in the collection using the black light traps. The adult population densities of Anopheles sinensis peaked at an average of 200 in Gwangam-dong, Dongduchen-si in July and an average an average of 977 in Songsan-dong, Uijeongbu-si in August. Nocturnal Activities of Anopheles sinensisn peaked at between 22:00 ∼23:00(21.0%) and 16.4% between 21:00 and 22:00, 13.1% between 23:00 and 24:00, 13.0% between 20:00 and 21:00, 11.7% between 24:00 and 01:00 in averages.