The research objective of this study was to assess the Determinants of Participation of Multipurpose Agricultural Primary Cooperatives in Cooperative Affairs: A Case of Bahir Dar Zuria District in Amhara Region of Ethiopia. The research design of the study was descriptive research design and the research approach of the study was a mixed approach that was both qualitative and quantitative. Thus, a three-stage random sampling procedure was adopted for the selection of the sample respondents from the cooperatives in the selected woreda. In this regard cooperative members were selected by using availability sampling technique and comprehensive sampling technique was used to select both cooperatives management committees and employees. The data source of the study was primary data. Incidentally the data collection instruments of the study were semi structured interview schedule for members and closed questionnaires for employees, interview for managing committee and focused group discussion for members. The data analysis techniques were descriptive statistics, Econometric and qualitative technique were employed. To analyze the factors that affect members’ participation and members’ participation logit model and OLS was applied respectively, independent sample t-test was employed to see the significance mean difference between passive and active participants. Besides these descriptive statistics were used to describe the basic features of the data and also applied for the analysis of challenges and prospects in MAPCs input output marketing in a study. The findings revealed that Family size has negative and in significance effect, Distance from multi-purpose agricultural primary cooperatives to the household house had found negatively determining the members‟ level of participation ,Duration of membership in cooperatives had found positively determining the household level of participation, Educational level of respondents had found positively determining the members’ level of participation, landholding has influenced positively the agricultural input and output marketing activity. A combined effect of the factors included in the model reveled that about 60.8% affected by the predetermine variables .Conclusion from the obtained result family size, membership duration, credit access and distance of house hold from cooperatives have negative effect. Therefore, the local government should create a mechanism to improve members participation by considering family size, duration of membership in cooperatives,, educational level and land holding. Key words: Multipurpose Agricultural cooperatives, participation, participation index