Abstract
In a context of organizational change this article analyses supervisors' positions and personal power bases and the influence they have on the co-operative behaviour and organizational commitment of their subordinates. Data were collected from a sample of 78 subjects who had at least one year's full-time work experience. A structural model was tested and the main group of results showed that supervisors' reward and expert power bases were positively associated with their referent power bases, which influenced their subordinates' co-operative behaviour and organizational commitment. The implications for managerial practices are discussed.