The aim and objective of this paper is to analyse the development of the contract law of the European Union and review the main changes introduced by the European Parliament Legislative Resolution on the Common European Sales Law compared to the original Proposal for a Regulation from 2011. At the beginning of the paper, an overview of the development of the European Union's contract law over the last decades is presented. It includes various Directives and the Principles of European contract law by the Commission on European Contract Law. The paper further continues to explain the ordinary legislative procedure in the European parliament and to show the process of adopting the Legislative Resolution on the Common European Sales Law to its adoption in the Council. The legal basis for its adoption is analysed in sequence. Furthermore, the structure and content of the Proposal and the Legislative Resolution is outlined. Finally, the new provisions of the Common European Sales Law that have been adopted by the European Parliament are explained.