This master thesis deals with the transfer of personal data from the European Union to the United States of America under Regulation (EU) 2016/679 of the European Parliament and of the Council of 27 April 2016 on the protection of natural persons with regard to the processing of personal data and on the free movement of such data, and repealing Directive 95/46/EC. The provisions of the Regulation which represent the legal bases for the transfer of personal data to third countries, namely adequacy decisions, appropriate safeguards and derogations for specific situations, will be analysed. The focus of the paper is on the scrutiny of two decisions on the appropriateness of the transfer of personal data from the EU to the USA and on the case-law of the Court of Justice of the European Union, which decided, inter alia, on the validity of those decisions. The decisions are Safe Harbour and Privacy Shield decisions, while the key cases of the Court of Justice of the European Union are Maximillian Schrems v. Data Protection Commissioner of 2014 and the Data Protection Commissioner against Facebook Ireland Ltd., Maximillian Schrems of 2018.