The aim of this paper was to examine the organizational changings of agricultural cooperatives in Vietnam under market economy. 3 safe vegetable cooperatives which were differing in establishing background and process, means transformed one, re-established one after cooperative low, and newly established one, were selected as sample and the difference of function in marketing and organizational structure were compered. Results showed that each cooperative had different function in safe vegetable marketing. Transformed cooperative outsourced the marketing and distribution work to another company by contract, re-established cooperative focused its activities to production for conclusive transactions with its client. And newly established cooperative officially had marketing division however the income from this division was not collected to the administration. The activities of cooperative were also changing from farmer’s support to commercial business beside. In parallel, the organizational structure of cooperative is changing from traditional community based to market oriented. The way of benefit allocation, decision making, characteristic of members are changing along establishing of cooperative process. In the future, the organization models of agricultural cooperative will be varied. We need to think what will be the effective organization for farmers who need self-help organization under rapid economic development, based on the consideration of historical process and position of agricultural cooperative in agricultural policy in Vietnam.