Dairy cooperative structures in Ireland have evolved through time. Ireland’s twentieth century dairy cooperatives emerged in a market environment that is vastly different from the one in which they operate today. This paper looks firstly at the broad evolution of structural changes in Irish dairy cooperatives. It then examines the question of cooperative culture as a factor shaping the direction of change. The relevance of the “small is beautiful” thesis is briefly considered and we argue that it is too simplistic an approach for evaluation of dairy cooperatives today.