The study aimed to determine the level of knowledge of the surveyed farmers on the neg-ative effects of the use of chemical pesticides, and their sources of information in this field, and determine the significance of the relation-ship between the level of knowledge of the farmers with the negative effects of the use of pesticides and some independent studied vari-ables, and finally identify the problems that limit the safe use of chemical pesticides ,the data of this study were collected during July and August 2020 by means of a personal inter-view questionnaire for a regular random sam-ple of farmers in the villages of Qalyubia Gov-ernorate. It was determined using the Kreijce and Morgan equation, and its strength reached 377 farmers, The selected data were analyzed and presented using quantitative method, the arithmetic mean, Chi-square test, The most important results were the following :the level of the respondents' knowledge of the negative ef-fects of using chemical pesticides was high, with the percentage of their average knowledge scores reaching 82.9, It was found that the most important sources of information: pesticide merchants, personal experience, rel-atives, It was found that there is a significant relationship at the level of 0.01 between the level of the respondents' knowledge of the neg-ative effects of chemical pesticides and each of the following independent variables the re-spondent's age, gender, educational status, profession, number of years of experience in farm work, social participation, Frequency of agricultural service centers, and the number of years of experience in using pesticides. It was also found that the most important problems in the research area are: the shortage of extension agents, the scarcity of extension activities, re-spectively, Based on the results of the study, six proposals were formulated in the form of recommendations to be submitted to decision-makers.