Summary — The purpose of this essay is to reconstruct the concepts of social and functional integration in Talcott Parsons, after the critics raised by authors like Lockwood, Moutzelis, Giddens, Habermas. The author shows that the two concepts are complementary, not in contradiction. Furthermore, this complementarity presupposes and entails the autonomy of actors and the possibility of conflict. So, in the light of this reinterpretation, the theory of general system of action represents one of more powerful tools for the social analysis. The theoretical model is applied to the analysis of complex organizations in contemporary societies.