Fundamentally, what is of interest in this thesis is whether the currency union of the European region has actually delivered with respect to removing barriers to entry and hence creating a more open market. Consequently, this should result in enhanced competition and therefore a decrease in market concentration and firm profitability.  Significant research has been undertaken with respect to country and therefore macroeconomic impacts. However firm and industry behaviour on a microeconomic level has been largely ignored. Most analysis to date focuses specifically on industries within countries and not across countries in general. Furthermore, there has been no research to date that specifically investigates pre and post impacts of the Economic and Monetary Union (EMU).  The determinants of market concentration and firm profitability are explored at length; leveraging the Cournot model. The Herfindahl-Hirschman index (HHI) is constructed across eight different market definitions, in order to capture the impact of the EMU on market structure. The models generated for market concentration (i.e. HHI) and firm profitability (i.e. ROS, ROA and ROE) deploy panel data estimation techniques.  According to the models estimated the creation of the EMU has resulted in a reduction in market concentration and firm profitability, consequently suggesting an increase in competition. In light of recent events, policy makers need to be very careful when considering potentially breaking-up the EMU, as there may be direct negative consequences pertaining to the levels of competition across the European landscape