Research on co-operative organizations has posited member commitment as a critical issue for sustainable and successful co-operation. To our knowledge, none of the previous works have focused on normative commitment to map accumulated knowledge on the members’ sense of obligation to maintain patronage of the co-operative. It is towards these ends our work is directed. More specifically, our paper creates value for future research and practice of co-operation by identifying four sources of normative member-commitment: 1) coalition awareness, 2) internalization of co-operative philosophy, 3) identification with the coalition and 4) recognized realization of co-operative values and principles.