||This bachelor thesis called Antitrust policy from a point of view of institutional economics is considered to be a sort of enlargement of conventional approaches of antitrust policy toward different market structures. It begins with a short introduction into antitrust and basic causations of market structures, conduct of market entities and total performance. The central point of this paper concerns an analysis of different market structures and the anticompetitive and pro-competitive behaviour they initiate. In each chapter, the optimum approach of antitrust policy I provided as well as the extent and form of intervention designed to eliminate the anticompetitive impact of such structure and spur the efficiency. The analysis reflects not only the conventional economic principles, but contributes with the institutional ones. Many of antitrust litigations are mentioned in this paper to demonstrate the link between the theory of market competition and the practice. First, the paper focuses on horizontally and vertically integrated firms. Then it discusses a particular market industry – the network industry that creates a specific market structure. Later on, there is a state aid discussion and its potential anticompetitive impacts not only in one state economy but also within the framework of the entire European Union. Finally, there is a description of a special sort of market called contestable market – a concept created in late 80´s which has a potential to influence the antitrust policy, but which is widely considered to bunfeasible because of its unrealistic presumptions.