This study aims to answer the main questions "Does the motivation of Co-operative Board of Directors affect the Co-operative's performance in Thailand, and to what extent?", and "Which factors affect the motivation of Co-operative's Board of Directors?" The methods used consist of both quantitative and qualitative approaches: Structural Equation Modeling (SEM) and in-depth interview, respectively. The study result suggests that the motivation of Co-operative Board of Directors significantly affects the Co-operative's performance with a standardized factor loading of 0.144. Surprisingly, the types of motivation that affect the Co-operative's performance are not those of altruism, but they are those of personal interests, i.e. to gain reputation from the community or society, to obtain honors or awards, and to gain the feelings of accomplishment from working. However, this result is subject to the condition that cooperative performance is measured solely in financial terms and quality of management. This is due to the current limitation in standardizing the measurement of cooperative performance in social terms and should be left for future research. Factors that are found to affect Board Member motivation include the knowledge, skills and experience possessed by the Board Members, Board authority and function, the composition of the Board (the presence of external persons) and lastly, the quality of the Board meetings. Specifically, Board authority and function is the characteristic determining whether the Board is involved in the Co-operative operation. Factors whose relationship with Board motivation was not found included the one person one vote principle, Board size, chairman-manager duality, Board term, and Board structure (the presence of a compound Board).