This paper investigates the opportunity of a Procompetitive interpretation of Private Law through an interdisciplinary analysis of Competition Law with Contract Law. The purpose of the research is to demonstrate that the traditional Civil Law might be differently considered and interpreted in the specific market where contractual obligation arises. Under this point of view, for example, it is necessary to adopt a new approach to the traditional notion of legal consideration of the contract, to the ancient rule in pari causa turpitudinis melior est condicio possidentis, to the doctrinal category of protection obligations. All these institutions should be directed not only towards assuring contractual economic balance, but also towards regulating the whole market in which the single contract is done. In this way the interplay between Private and Public interests becomes decisive to make Economy and Freedom of Contract more consonant with the value of Human Person.