In this paper is analysed the volume of Amartya Sen The Idea of J ustice. Here are considered and discussed the methodological foundations and the goals proposed by Sen, establishing a conception of justice that must actually emerge in a society through the public debate, and the implications above all terms of reduction of the most resounding injustices, still existing in many societies. In this analysis one gives evidence to the conceptual ancestors probably in contradiction in the Utilitarianism of Jeremy Bentham and John Stuart Mill, and some theoretical difficulties that seem emerge in the Senian elaboration.