The last few decades witnessed the rise of new approaches or frameworks in the study of International relations. These new approaches are called post positivism. Most of these approaches share a common view regarding the positivist theories which dominated international relations and political science for more than sixty years. The new directions criticize the methodology and the epistemological and ontological assumptions of positivism. In this paper we try to evaluate the contribution of the positivist theories in international relations and the arguments of the new approaches, mainly Critical theory, post-modernism and social constructivism.