This paper aims to explain the participative behavior of farmers-members of agricultural cooperatives in the governance of the latter. The study introduces two concepts from the organizational behavior literature: trust and organizational commitment. It tests a mediator effect of commitment in the relationship between the trust a farmer has in the cooperative and his/her participa-tive behavior in its governance. Based on a sample of 259 members of French agricultural cooperatives, results showed that affective commitment had a mediating role in the relationship be-tween trust and participation in the governance of cooperatives, notwithstanding the cognitive or affective nature of trust.