Organized crime in Ukraine presently constitutes a serious problem, which requires a reaction of the government in the area of penal law. Consequently, the Ukrainian Penal Code of 2001 includes (along a number of other regulations) a provision that penalizes establishing, participating in, and leading a criminal organization (Art. 255 of PC). In order to better explain this provision, first the terms 'criminal group' and 'criminal organization' were discussed (Art. 28 items 3 and 4). Their quantitative (three or more persons) and qualitative (organized nature, permanence, planning, division of tasks) features were indicated. This was a basis for the demonstration of differences between the two types of organization. By using the statutory features, a crime covered by Art. 255 of PC of Ukraine was then discussed. Particular attention was paid to the objective aspects of the crime, in order to demonstrate its complexity. Also, the provision of Art. 255 item 2 was presented, which allows for the possibility to become relieved of the penal responsibility for the commission of the crime under Art. 255 item 1. The premises for using this institution, among others informing appropriate government bodies of the establishment of a criminal organization and participation in it, as well as an active cooperation in detecting its criminal activities. In the conclusion, several remarks and doubts were expressed, concerning the regulation in question. This constituted a reference to Polish regulations, and an indication of a lack of clear rules on establishing, leading, or participating in an organized criminal group.