The recent proposal for a Regulation of the European Parliament and of the Council on a Common European Sales Law, gives us the chance to make a few brief comments and criticisms concerning its application and adaptation of the Spanish legislation. Indeed, it has been made a thorough study of the Community rules on the concept of contractual offer on the international level, as a frame of reference, not only our own domestic law, but also the uniform law and the latest European contract law, perceiving its possible additions. Thus, the existence and importance of an optional regulation highlights the desired unification of the law of contracts, giving special importance to the study of concrete issues, such as the configuration of the offer and its erfection, the possibility of its revocation and expiry, which in this work are discussed in depth.