The principles of „Public Procurement” are important for the proper functioning of the public procurement system. There is no doubt that principles of public procurement system have a special significance for the above mentioned system, since they indicate the direction of interpretation of provisions of the public procurement law as well as they allow a proper interpretation of the meaning of legal norms. The purpose of this elaboration is to present two basic principles of the public procurement law, i.e. the principle of fair competition and equal treatment of economic operators as well as the principle of transparency. The Author indicates the institutional expression of these principles in the procedure of awarding public procurement and indicates the violations of the principles which occur in the practice of law.