This study aimed mainly to assess the impact of agricultural extension fieldson farmers' knowledge about bio-fertilizers in Kafr El-Sheikh governorate byidentifying the level of respondents' knowledge about bio-fertilizers; identifying the level of knowledge about bio-fertilizers for extension field owners, extension fieldneighborhood's farmers, and the control group farmers; and identifying theopinions of respondents in the technician conditions of extension fields. This study carried out in Kafr El-Sheikh governorate, and Kafr El-Sheikh district wasrandomly selected. An experimental design was planned and implemented; thedesign included forty extension fields in four villages. The design included three different groups, mainly, owners of the extension fields (40 farmers), extensionfield neighborhood's farmers on both sides (80 farmers), and one control group of40 farmers. A total sample of 160 farmers was selected. The subject-Matter of the experimental designs was the four bio-fertilizers of Bluegreen, Phosphorine,Cerealine, and Biohumine. Data were collected after harvesting the extensionfarms. Data were collected by personal interview questionnaire with trainedinterviewers  . Collected data were coded and analyzed using the SPSS package.Frequencies, percentages, mean, and "F" test were calculated.The main findings of the study could be summarized as follows:1- The mode of respondents response regard to the four studied bio-fertilizers ofBluegreen, Phosphorine, Cerealine, and Biohumine was in the category of medium level of knowledge with ratio of 53,8%, 56,9%, 62,5%, 45%; respectively.2- The mode of extension field's owners was in the category of high level ofknowledge about bio-fertilizers; the mode of extension field neighborhood's farmers was in the category of medium level of knowledge about bio-fertilizers,and the mode of control group's farmers was in the category of low level ofknowledge about bio-fertilizers.3-There were significant differences at the 0, 01 level between means ofknowledge about the four studied bio-fertilizers for extension field's owners,extension field neighborhood's farmers, and control group's farmers. Mean scoreswere highest for extension field's owners, followed by extension fieldneighborhood's farmers, and the control group's farmers.4-The vast majority of respondents (92%) saw that the technician conditions ofextension fields founded at moderate and high level.5-The mode of respondents response regard to the technician conditions items ofextension fields was in the category of the answer with "Yes".