Cooperatives are facing the challenge to be competitive in the market, without losing their traditional values of mutuality and democracy. To do that, they need to re-construct open and participative dialogue with their employees and members based on more democratic forms of communication and engagement. From this point of view, the measurement and communication of sustainability aspects may allow a dialogue to be mobilized with shareholders and stakeholders without losing the attention on competitive factors. Based on these premises, the article analyses the experience of a 5-year action research project (from 2006 to mid-2011), carried out within Unicoop Tirreno, an Italian consumers’ cooperative, and aimed to implement different tools for sustainability accounting and to embrace a more open dialogue with stakeholders, in particular with employees and members. In this process of change, the tools implemented for sustainability accounting played a key role in supporting the cooperative to reinterpret its own values and in stimulating a new and participative management approach. The results indicate a virtuous circle between the management and measurement of cooperative principles and the management and measurement of sustainability issues.