SIGMA Brief 1 provides a description of the legal framework of the EU public procurement system: two “procedural” Directives for the public sector (2004/18/EC) and for the utilities sector (2004/17/EC), and two other “remedies” Directives (89/66/EEC, 92/13/EEC, both amended by Directive 2007/66/EC). Additionally, Directive 2009/81/EC applies to the procurement of military supplies, works and services. In order to understand the basics of public procurement in the European Union, it is necessary to look not only at the Directives themselves but also at the general principles contained in the Treaty on the Functioning of the European Union. The Treaty principles guide the interpretation of the Directives. It is also important to understand the role of the various European institutions (European Commission, Court of Justice).