The article addresses a problem of a lower retirement age for women reintroduced in Poland in 2017. The Authors make an attempt to answer a question if this unequal treatment of men and women constitutes temporary special measures or affirmative action as interpreted in international human rights system, or if it constitutes discrimination on the ground of gender. The legal analysis is conducted from the perspective of constitutional norms and the case-law of Polish Constitutional Court, as well as on the basis of international human rights standards developed by, inter alia, CEDAW and ECtHR. The article thus complements the existing vast scholarship that is concentrated on analyzing the topical problem form the angle of labour law and social security law. The Authors conclude that a lower retirement age for women is an example of a direct discrimination de iure, because such difference in treatment based on gender cannot be rationally justified and is not proportional, which makes it discriminatory.