The current research is of survey research type that investigates the impact of farmers' field school (FFS) on the rice farmer’s knowledge, adoption and attitude toward Biological Control in the city of Babol, Iran. In this research the causal-comparative method was used to compare two groups of rice farmers. The Krejcie and Morgan’s table was used in order to access the intended data. The statistical sample of the research is (n= 472) which included 92 people of the rice farmers who attended the Farmer Field School and 380 people who did not participate in this course. Finally, to distribute the questionnaires between the two groups simple random sampling has been used. Meanwhile, 433 questionnaires collected were analyzed by SPSS software (81 of the rice farmers participated and 352 rice farmers that did not participate in the FFS). The findings show that rice farmers who attended the FFS have benefited higher levels of adoption and attitude toward the biological control compared to those did not attend this course. It is recommended that those involved in this issue pay special attention to hold these courses.