125 POLISH REVIEW OF INTERNATIONAL AND EUROPEAN LAW 2020, Vol. 9, Issue 1 Łukasz Kułaga* THE IMPLEMENTATION OF INTERNATIONAL AGREEMENTS IN THE POLISH LEGAL SYSTEM. THE SELECTED ASPECTS OF PRACTICE IN RECENT TWO DECADES Abstract: Te issue of the implementation of international agreements in the domestic legal system is of substantial signifcance. It guarantees the efciency of international law in the domestic space. Te article presents the selected aspects of this process in reference to the practice of the Republic of Poland, within the last two decades with the particular consideration of the position of the Council of Ministers in this respect. Te subject of analysis is the legal character (and its sources) of the obligation of the implementation of treaties, both at the level of international and domestic law. Subsequently, the conditions of the implementation have been considered, including the costs and the issue of application of international agreements. Te consequences of non-implementation of a treaty for enforceability of its provisions within the Polish legal system constitute the subject of the analysis in the last section of the paper. * Assistant Professor, Department of International and European Law, Cardinal Stefan Wyszyński University in Warsaw, ORCID: 0000-0003-0784-8293. Te article represents exclusively the private views of the author. Te author would like to thank Michał Kobyliński and anonymous reviewer for their helpful remarks. All the mistakes are the sole responsibility of the author.