Strategic alliance and joint venture agreements are analyzed using the prisoners' dilemma and assurance problem models of game theory. Hypotheses regarding the factors contributing to the success/failure of the agreements are formulated. These hypotheses are confirmed with data from interviews with managers of grain marketing cooperatives in eastern Colorado. Our results suggest that joint venture and strategic alliance agreements represent an opportunity for local cooperatives to take advantage of size economies while maintaining their individual business identities. Successful agreements require not only attention to the financial and operational components but diligence in the interpersonal dynamics of trust, commitment, and open communication.