Abstract. Market including public places as a place for interaction. According to the Decree of the Minister of Health of the Republic of Indonesia Number: 519 / Menkes / SK / VI / 2008, traditional markets are markets that mostly sell daily necessities with simple trading practices and do not heed the health rules. The density of flies is an indicator of how poor waste management or poor sanitary conditions are. The purpose of this study is to determine the relationship between the level of knowledge, attitudes, and actions of traders in managing waste with the density of flies in the Sembung Village Market in 2020. This type of research is observational analytic research with all population techniques used as samples and Chi Square test. The number of respondents in this study were 48 traders. The results of this study indicate that respondents have an unfavorable level of knowledge with high fly density (54.2%). Respondents' attitudes indicate that the attitude of unfavorably high fly density (54.2%). The respondent's actions were not good with high fly density (56.3%). The level of density of flies with high categories was more (56.3%). Statistical test results using the chi square test obtained p value = 0,000 α (0.05) which means Ho is rejected or there is a significant or significant relationship between the level of knowledge, attitudes, and actions with the level of fly density.Keywords: