Procurement of goods, works and services has always been an integral part of human life and business operations. All natural and legal persons at any moment of their existence, in order to satisfy their life or business goals, had and have the need to purchase various goods, works and/or services. This procurement de facto takes place through a kind of buying and selling relationship that is established between the ordering party on the one hand and the suppliers chosen by them for those goods, works and/or services on the other hand. An integral and inevitable part of every purchase and sale, including procurement, is the money that the customer gives to the chosen supplier of goods, works or services. Private purchasers, be they natural or legal persons, satisfy their own needs and spend their own money during procurement, while public purchasers in procurement spend mostly public budget money and satisfy the public interest. It is precisely this fact that requires the most economical and transparent use of public money from public contracting authorities, and in order to achieve this, a clear and unmistakable formal legal regulation of procurement procedures for public and sectoral contracting authorities is necessary. The prerequisite for such use of public money is the procurement of goods, works and/or services through market competition, i.e. through public procurement in which a wide range of interested economic entities will be able to participate. Considering that among them there will also be those economic entities that in their previous participation in public procurement procedures behaved inappropriately and/or illegally or that their responsible or authorized persons behaved in such a manner, the legislator also prescribed criteria in the Law on Public Procurement which public contracting authorities must use in the selection of an economic entity that will participate in the announced public procurement procedure. Accordingly, this thesis focuses special attention on the assessment of the ability of economic entities in public procurement procedures, and in connection with this, the reasons why public contracting authorities must or can exclude, colloquially speaking, unsuitable economic entities from the public procurement procedure. The purpose of this paper is to analyze the legally prescribed criteria for selecting an economic entity and to point out the reasons for their exclusion from public procurement procedures. The aim of the paper is to contribute to greater legal certainty for all participants in public procurement in the application of legally prescribed criteria for selecting economic entities and the reasons for their exclusion from public procurement procedures.