Abstract. Economic reality has dramatically changed in the 21st century. Competition and monopoly behaviour are under radical transformation due to digital effects in contemporary business world. Digitalization has engendered many new types of monopolistic conduct and deeply altered traditional forms of firms’ misconduct. In a digital era, the antitrust policy should rethink its concepts of regulation, market power, and anticompetitive behaviour. The analysis of contemporary competition policy in different countries shows that traditional antitrust rules could not effectively deal with digital activity. Having entered even in an ordinary space of anticompetitive firm behaviour, digital world has challenged traditional concepts of antitrust policy. The antitrust rules that dominated in the 20th century are mostly outdated when applied to digital era trends. What should and could competition policy do to meet the requirements of the 21st century? The article touches upon contemporary foreign investigations in the sphere of competition and competition policy. Our analysis demonstrates the challenges that are under way in antitrust regulation. Special attention is paid on new patterns that characterize traditional forms of monopolistic behaviour (cartels, dominant misconduct, predatory pricing, exclusive dealing, etc.) in a digital world. There was drawn the conclusion concerning the vital necessity of a cardinal transformation for the antitrust policy from a hard state controller into a flexible business consultant, with the aim not to punish but to prevent market misconduct.