Purpose - Cooperatives are people-centric organizations that are organized to meet the common needs of their members. One key goal for the establishment of agricultural cooperatives is to help improve the marketing efficiency of their members. This study aimed to analyze the correlation between cooperative membership and marketing efficiency among coffee farmers in the provinces of Cavite, Benguet, and Mountain Province, Philippines. Design/Methodology/Approach - Primary and secondary data were gathered in the study. Linear regression with endogenous treatment was used to analyze the data which examined both observable and unobservable factors affecting the treatment, cooperative membership, potential outcome, and the marketing efficiency. Findings - The results of the study revealed that the average farmer generated USD0.85 more farm income for every peso spent on marketing activities if he/she was a member of an agricultural cooperative. This implied that membership positively improved the marketing efficiency of coffee farmers. Moreover, farmers who sold their processed coffee to cooperatives and who had price access were observed to have higher marketing efficiency. Farmers who were females, adopted more processing technologies, took longer to search for price information, sold to cooperatives, had more coffee experience, and whose farms were located away from technology sources were more likely to become cooperative members. Research Implications - The study recommended the promotion of cooperative membership among farmers to improve their marketing efficiency and capacity-building activities related to the technology adoption and management of cooperatives.