This paper aims to present some preliminary ideas about the potential benefits and costs arising from the process of European Contract Law harmonization for the functioning of the existing national Contract Laws, and in the end, for the welfare of European societies. Some of those benefits and costs will essentially be illustrations of some relevant generic features of a legal harmonization process abstractly considered, whereas others will apply specifically to the current process under way in Europe and affecting European Contract Law. Section 1 serves as introduction, Section 2 would first present and then examine the potential benefits of the harmonization process, while Section 3 will deal with the reverse side, that is, with some of the potential risks, broadly understood, of the harmonization endeavor. Section 4 briefly concludes.