Flies were collected using putrefied baits once a week, a total of 40 times in a housing area of Pohang City(POSCO housing complex), Korea from August 1, 1993 to July 31, 1994. The number of flies collected was 18,037 with sex ratio(male/female $ imes$ 100) of 41 and fauna of the fly was to 23 species. In the comparison of the individuals of each family collected , Calliphoridae occupied, 69.1% of the total catch, Muscidae 17.2%, and Sarcophagidae 13.7%. In the comparison by traps of the numbers of species and individuals collected, 8,938 individuals in 23 species were collected at Trap 1, and 9,099 individuals in 21 species, at Trap 2. The five predominant species, Calliphora lata, Lucilia caesar, Aldrichina grahami, Hydrotae-a dentipes, and Chrysomyia pinguis, constituted 70% of the total collection. In the prevalence of the total from beginning of March to the end of December, the peaks of the male appeared in April and May, and those of female in April and November. The pattern of the trap which was set in a residental area was almost same with the trap which was set in a small moutain near to the residental area. So, it considered that the environment of the residental area was affected by the surrounding small moutains. The correlation between the total number of fly individuals and that of species collected with two traps was found to be very close. The characteristics of five predominant species in the collection were summarized, and their seasonal prevalence and monthly change in the composition of flies collected at each trap were also compared.