The unilateral right of a member state to withdraw from the EU is an entirely new feature of EU Law introduced by the Lisbon Treaty. The practical application of the withdrawal clause was placed on the agenda as a result of the 23 June 2016 Brexit- referendum in the UK. The exit raises some non-legal and legal, theoretical and practical issues which – as we are talking about an unprecedented event – have to be elaborated on now. The paper analyzes Article 50 TEU by analytical methods, summarizing the incomplete frameworks, the main procedural rules, and those issues that require the interpretation of the Court of Justice of the European Union. The paper aims to highlight the points of the withdrawal clause that have interpretative gaps, which might not have been unintentionally left by the EU legislator.