Research on the supervisory boards of cooperatives has been scarce considering their prevalence, especially in continental Europe. The supervisory board is a voluntary body under Finnish conditions and consists exclusively of members' representatives. According to the cooperative law, the task of the supervisory board is to supervise the board and management. Based on the results of this article, the role of the supervisory board is changing in a more dynamic direction, which includes sparring with the board, taking care of the ownership strategy and developing interaction with the membership. Hence, it would fulfill not only the conformance role of the governance towards the membership but support the performance role of the board. This new role would require re-assessment of the selection criteria for the members of the supervisory board, not merely from a representational perspective, but also from the perspective of competence adequacy. The supervisory board and its chairperson are significant users of the power based on their formal position in preparing and electing directors. They also use the informal power in interaction with the board and its chairperson.