An administrative contract is a specific contract with a special legal regime, subjects and characteristics that classify it as an institute between private and public law. The paper presents a comparative analysis of the general principles of contract law, and above all civil (private) law and administrative contract. This analysis should answer the questions of the basis of the contractual obligation, ie the basic elements that create a contractual obligation. The paper presents the most important principles, as well as general elements of the contract on the one hand and basic characteristics of the administrative contract on the other, in order to better understand their legal nature, similarities and differences, especially the legal nature of the administrative contract and its place in contract law.