Agricultural cooperatives in Cambodia have been promoted with the aim of increasing agricultural production and farmers' revenues. The objectives of this study are to identify factors influencing farmers' decision on membership in agricultural cooperatives, and to assess the impact of being a member in those cooperatives on farmers' revenues from paddy, livestock and farm. Cross-sectional data from interviews of 242 households in Tram Kak District, Takeo Province were used. The probit model and propensity score matching were employed to achieve the objectives. The results show that farmers who sold their paddy and had been contacted by extension workers from the government agency and non-governmental organizations (NGOs) are more likely to join the cooperatives while male-headed household farmers and farmers who have high off-farm income are less likely to become members of the cooperatives. Moreover, the results of propensity score matching reveal that agricultural cooperatives have no impact on paddy yields and paddy revenue due to the fact that agricultural cooperatives do not provide sufficient training to their members, and members did not actively attend those trainings provided. Also, the cooperatives have failed to provide members better prices for their paddy. There are positive impacts on their livestock and farm revenues through increasing livestock and other crop production when agricultural cooperatives provide livestock and other crop training to their members. However, there is no impact on non-members if they join the cooperatives as they have higher off-farm income, less paddy land size and fewer laborers that are not favorable to taking on other farming activities.