Contracts of the administration, which are classified as administrative contracts and private law contracts of the administration, inspired by the principles and rules of private law. However, based on the distinction of public law-private law; a legal regime of contracts of the administration, differing from the regime of contracts concluded by private persons, has emerged. Because of the administrative law and financial law principles and rules, the regime of the contracts of the administration is autonomous. Contracting procedure of the administration is both a basis and a result of this autonomy. Contracting procedure of the administration also constitutes the common point of the administration's administrative and private law contracts. On the other hand, this procedure is the reason why the contracts of the administration differ from private law contracts. There is an intersection in terms of public service, public interest and public finance in all contracts of the administration. This intersection gives administrative nature to the process until the contract is concluded in all contracts of the administration. In addition, the administrative nature resulting from this intersection is the existence of a single contract concluding procedure in the contracts of the administration. In this context, public procurement principles such as openness, competition, competence and the most appropriate price constitute the principles and essences that apply to contracting procedure of the administration.