We analyse trends in inflation-adjusted audit and non-audit fees from 2003 to 2009 with the aim of identifying the impact of International Financial Reporting Standards (IFRS) in Spain, where (a) the shift from national to international accounting standards represented major changes and (b) the implementation process was conducted in 2005 for group accounts of listed companies and 2008 for the individual accounts. To that end, we build a well-tested audit and non-audit fee model based on 2003 and compare the actual with the predicted values had the accounting reforms not taken place. We report unexpected higher audit fees for the group accounts model in the years 2004, 2005 and 2006. A plausible explanation for these results is the incremental audit costs associated with the mandatory IFRS adoption. Similarly, the unexpected increment in 2008 for parent company audit fees is feasibly associated with the new domestic accounting rules. The behaviour of non-audit fees is more erratic and likely influenced by the auditors' independence regulation enacted in 2002. We only identify significant prediction errors in