This paper addresses the question whether the mandatory adoption of International Financial Reporting Standards (IFRS) is associated with higher accounting quality. More specifically, we investigate whether the application of IFRS in 15 European Union (EU) countries is associated with less earnings management and higher timeliness, conditional conservatism, and value relevance of accounting numbers. Our results suggest that there has been some improvement in accounting quality between the pre- and post-IFRS adoption periods. In particular, we find that firms exhibit an increase in the accounting-based attributes, but a decrease in the market-based after the adoption of IFRS in 2005. Interestingly, the findings are more pronounced for the firms in countries where the distance between the pre-existing national GAAP and IFRS is important. Furthermore, we are unable to identify any change within firms that have converged their local GAAP toward IFRS before the mandatory transition.