This study shows the importance of the power concept in organizations and suggests, that the understanding of this reasoning becomes a necessary tool for improving individuals' behavior in current organizations and improving the Business Administration practice. In the organization's analysis and its relationships with power, an instrumental and pragmatic point of view has being dominant, with pretended universal characteristics. This is, how power is exercised and its efficient and strategic use. This article makes a theoretical review about the power concept in organizations, while contrasting some authors definitions, mainly Max Weber's and Michel Foucault's. It will be shown the instrumental and hierarchical approach to power and the more comprehensive and differentiator approach of Foucault's. Also, a brief review of some business administration academics contributions about power and its exercising in the organizations will be done, showing how Michel Foucault's approach gives a new broad and different notion that transforms the traditional boundaries, restricted to functional forms and positivistic organizational thinking.