The organizational growth of farmer cooperatives is tied to increased heterogeneity in member attitudes and perceptions. To inform possible solutions, a better understanding of the complex interrelationships of member attitudes and perceptions is necessary. Using survey responses from 1,116 members of an organic marketing cooperative in the United States, this paper develops a structural equation model of six factors: organic lifestyle, mission support, participation, trust, satisfaction, and long-term commitment. The final model illustrates nine significant relationships, including satisfaction and long-term commitment. The result suggests the long-term survival or viability of farmer cooperatives is not only dependent on its financial performance but also the utility of its members. In terms of member attitudes and perceptions, trust and mission support may offer the best opportunities for farmer cooperatives to foster member satisfaction and thus address the negative consequences of heterogeneity.