This paper compares socioeconomic and technical characteristics of dairy cooperative members and nonmembers based on a sample of New England dairy herd improvement association participants. Descriptive statistics indicate there is a little difference between the two groups. A high proportion of members stated cooperatives were helpful primarily because they provide a safe or guaranteed market. Estimates of a Cobb0Douglas production function suggest membership in one specific cooperative was positively and significantly associated with average farm efficiency. Results of a logit analysis indicate the probability of being a cooperative member was positively related to extension contracts and negatively related to output per cow per farm.