The topic of this thesis is the analysis of the case law of the Court of Justice of the European Union (CJEU) in relation to antitrust damages proceedings, as a means of private competition law enforcement. The adoption of Directive 2014/104/EU on antitrust damages resulted in an increased number of proceedings before national courts, and consequently in an increased number of requests for preliminary rulings before the CJEU. This paper analyses judgments of the CJEU and explain how they contribute to the creation of a clear judicial practice and increased legal certainty in exercising the right to full compensation. In this regard, special attention is given to the interpretation of the temporal, material and personal scope of application of the Directive, as well as the development of the concepts of undertaking, economic unit and economic activity in the context of competition law, with special reference to the impact of these interpretations on the enforcement of the Croatian Act on actions for damages for antitrust infringements. Finally, the paper touches upon the difficulties in private antitrust enforcement in relation to antitrust infringements on digital markets.