A theory of economic competition occupies a very important place in political economy, though its role is often underestimated and seldom correctly understood. Hence, the main purpose of the article is to undertake an attempt to evaluate the state of research and theory in that respect and to explain the essence of that theory, with critical reference to the existing research results. The article includes considerations on historical conceptions of competition (comprising A. Smith's dynamic conception of free competition, the model of ideal competition and the conception of monopolistic competition), the analysis of a modern conception of so-called "effective competition", the considerations on the functioning of an enterprise with...