Tomasz Lachowski Mag. iur., PhD Candidate The Chair of International Law and International Relations Faculty of Law and Administration, University of Łódź, Poland Published in: Сɭɱаɫɧɿ ɬɟɧɞɟɧɰɿʀ ɦɿɠɧаɪɨɞɧиɯ вɿɞɧɨɫиɧ: ɩɨɥɿɬиɤа, ɟɤɨɧɨɦɿɤа, ɩɪавɨ, (ed.) I. Byk, M. Makiyevych, N. Antoniuk, I. Hrabinskiy, Львів 2014, pp. 20-29. New dimensions of international law – the question of ius post bellum Summary This paper describes the notion of ius post bellum, crafted by the work of the international law scholars to fill in the gap of the lack of sufficient legal regulations in the post-conflict situations. Bearing in mind the development of international law and its ‘modern pillars’, like human rights law, international humanitarian law or international criminal law, it is worth mentioning the need of defining the post-violence scenarios and roles of actors involved. As it seems, ius post bellum appears to be the composition of norms, however not limited to, the abovementioned branches of international law, trying to shape the framework of: on the one hand, the ‘primary’ obligations of the affected, transforming state (in a transition from ‘war’ to ‘peace’), on the other, the duties of the external actors, being a part of the post-conflict environment. Thus, (UN) transitional administrations or other international, institutional presence, as under the label of the UN Peacebuilding Commission. The paper is intended to shed more light on the issue of ius post bellum by invoking its main features and a scope of the concept. Moreover, it is argued that at least some of the ius post bellum conditions are the part of different, existing or emerging concepts of international law, as the ‘Responsibility to Protect’ (R2P) or transitional justice mechanisms, implemented by post-conflict societies, setting accounts and reckoning with their past abuses, rooted in the conflict itself.