This work deals with legal aspects of collective dominant position under Article 82 of the Treaty establishing European Community (hereinafter- EC). The purpose is to reveal a legal definition and main features of collective dominant position. The author examines features and criteria which are established in the jurisprudence of EC institutions. The author examines features and criteria which are established in the jurisprudence of EC institutions. The author also indicates that the criteria for establishing collective dominance are not fully scrutinized under EC competition law. Moreover, the practice of EC institutions is analyzed not only under Article 82, which prohibits abuse of a dominant position, but also under Merger regulation to that extent which is necessary to reveal the main topic. Further the work presents problems which are found under these two institutions of EC competition law.