This thesis assesses the development of block exemptions in order to investigate the economic benefits and drawbacks of using this legal technique to regulate competition in the European Union. It examines the provisions of Article 81, the legal basis of block exemptions, and demonstrates that they do take into account economic considerations even if few shortcomings exist due to the way in which they have been interpreted. This thesis also discusses the main characteristics of block exemptions as a legal technique and the procedural rules which govern their implementation. It demonstrates that over time the importance of economic considerations has increased, which is a strong positive aspect in favor of block exemptions. Finally, the thesis looks al all past and present block exemptions issued in the different sectors of the economy. It shows that the evolution of block exemptions was a difficult process and that their content changed over time, sometimes significantly. This is why a simplification of their structure would be welcome in order to provide more flexibility so that the legal rules can adapt to changing economic circumstances without the need for them to be amended frequently. The thesis concludes that overall the benefits created by block exemptions outweigh their shortcomings and thus they are an effective legal technique for regulating competition law in the European Union.