The article is devoted to the analysis of DCFR and CISG, assessment of them as legal principles and social values, and thus establishing their importance for adapting the understanding of the essence of contract law of Ukraine to the European concept of private law. The article analyzes as topics of special interest the problems of contract formation, a doctrine on culpa in contrahendo, and standard terms or interchangeably general conditions. In this article, the author provides specific suggestions for improving the provisions of the Art. 650-1 UKR-CC concerning the liability for pre-contractual negotiations contrary to fair dealing. The application practice of UKR-CC is currently assessed positively, but the legal mechanisms of its action are subject to revision considering the experience of law enforcement and the interpretation of civil law by courts. Modern realities (economic, social, technical, informational) require legal certainty, because UKR-CC, like any codified act, possesses gaps and shortcomings in the presentation of legal material.