Despite studies which indicate that mandatory adoption of International Financial Reporting Standards (IFRS) reduced the cost of capital for adopting firms and improved analysts’ forecasts, the evidence supporting any improvement in accounting quality is mixed. In a European wide country study, we calculate a broadly based measure of earnings management defined as accruals which are unrelated to current activity or past-current-future cash flows. At the individual country level we find that accounting quality improved only in France, Germany and Netherland, which are categories as ‘legal origin countries’. Moreover, based on an equity valuation model adjusted for earnings quality, we find that, in most European countries, the market overreacted to the impact of mandatory IFRS adoption. Further test shows that investors do not seem to understand the exact components of the financial statements that IFRS will have impact on