The 48 members of the Ezemvelo Farmers' Organisation (EFO) in KwaZulu-Natal, South Africa (SA), that are fully-certified as organic farmers were surveyed in October-December 2004 to assess their perceived levels of satisfaction, trust, cooperation and commitment in a formal supply chain producing amadhumbes (a traditional vegetable tuber), potatoes and sweet potatoes for a major SA supermarket group. Empirical recursive models show that a high level of satisfaction in the working relationship results in these farmers trusting the pack-house agent more. High levels of trust, in turn, lead to higher levels of both commitment to, and cooperation in, the supply chain. A simultaneous-equation model showed that EFO members with higher levels of commitment tend to be more cooperative, and that members with higher levels of cooperation tend to be more committed toward the working relationship. These results suggest that strategies to improve the working relationship with the pack-house agent need to promote satisfaction, trust, cooperation and commitment. For example, co-investment in better crop storage facilities at farm-level would promote satisfaction and hence trust. There is also scope for more cooperation in the planning of new organic crop products to grow and market, and to remove some price uncertainty by giving EFO farmers more information about prices that they will be paid by the pack-house in this supply chain.