This study aimed to evaluate the loyalty of cooperative members in a state's agricultural cooperative 'delivery or not of its production in 2012/2013 harvest. We used the qualitative method, developed through a case study on Cooperative Tritícola Sepeense Ltda - COTRISEL. The study consisted is an applied research (bibliographical, documentary and direct), exploratory, aimed at generating practical application of information regarding the reasons that led the cooperative to deposit part or all their soybean production in the cooperative. The survey ranked the cooperative according to their faithfulness in delivery of soybean production in the cooperative. At the end of the study it was concluded that, overall, 63,9% of respondents were cooperative members loyal to the cooperative. Other 16,7% were moderately faithful; 11,1% were less faithful; and finally, 8,3% were unfaithful. The study found that the main factors that encouraged the loyalty of the members are related to the trust, honesty and credibility of the cooperative, punctual payments, storage structure, technical assistance, payment term of inputs to crop (financing cooperated ), affinity with the cooperative, distribution of net profits as social status and exchange-exchange contracts (grain for inputs). The factors that discouraged loyalty, reported by members, were the discounts granted by the cooperative at the time of delivery of soybean production, the price paid for soybeans (often cooperated find more competitive pricing in other establishments) and a lack of flexibility in receiving and soybean discharge.