The present research article seeks to analyze the main aspects of Hans Kelsen and Herbert Hart's theories of international law from a critical perspective. To achieve this objective, a content analysis is carried out based on the documental research of the direct work of the authors, other authors who revalue this work and exponents of the critical theory of international law and international relations. For the proposed analysis, the epistemological and normative planes of the aforementioned theories are separated, which concludes that there is a greater harmony between the positivist and critical theories as far as the normative plane is concerned, while in the epistemological there is a strong discrepancy, particularly with Kelsen's methodological positivism.