EN
The sector of small and medium-sized enterprises is perceived as an extremely important element in all developed economies due to its high development dynamics, effective use of resources, and role in new job creation. It is an object of numerous activities aimed at accelerating its development and growth dynamics. The basis of such activities is compiling a set of criteria allowing to distinguish as precisely as possible small and medium-sized enterprises from among all economic units. The article discusses the definition criteria of SMEs divided into three groups: qualitative, quantitative and mixed criteria, which is supported by examples. The application of all these criteria involves numerous difficulties. Those chosen from among them are analyzed in this article.