Given the legislative reform of family law and of private international law after adopting the new Romanian Civil Code that is subject to the modern legislations tendency of unification of the rules on matrimonial property regimes we will devote the present study to the law applicable to matrimonial agreement. In the elaboration of the study the starting point is the intern law. Based on what it is already acquired in the doctrine and jurisprudence, we will discuss the issues and new solutions offered by the new Romanian Civil Code. If during the study we shall find that certain legal rules do not cover scientific, practical hypotheses or if they are lacunary, incomplete, inconsistent, not in harmony with the European legislation we will give suggestions of lex ferenda.