From 1 January 2005, all EU-listed firms are required to prepare their consolidated financial statements in accordance with International Financial Reporting Standards(IFRS) (EU, 2002). This requirement represents one of the most fundamental changes to affect financial reporting in recent times. This dissertation is an examination of the introduction and impact of IFRS on the annual report and accounts of UK companies in an attempt to investigate the decision-usefulness of the new IFRS disclosures. This examination is facilitated in three ways: (i) a content analysis is undertaken to investigate the magnitude and nature of the changes in IFRS-related disclosure presented in annual report and accounts produced prior to and following the introduction of IFRS; (ii) an analysis of the Reconciliation Statements produced upon first-time adoption of IFRS included in corporate annual reports to examine the impact on both profit and equity as a result of the transition from previous national GAAP to reporting in accordance with IFRS; and, (iii) an assessment of the new IFRS disclosures against the qualitative characteristics outlined in the IASB Decision-Usefulnessfr amework. In other words, it is an investigation of whether the claims of the IASI3 about the usefulness of the mandated IFRS disclosures for decision-makers are supported in practice with the contents of corporate annual reports and accounts in the UK.The results of the content analysis indicate that the implementation of IFRS had a significant impact on the content of the annual report and accounts of UK companies.The amount of disclosure in company annual reports increased significantly following the introduction of the new reporting regime. Furthermore, there was a large increase in the physical size of the annual reports for the vast majority of the firms surveyed. The scale of the impact varied from standard to standard, however, the nature and magnitude of the information presented in UK-published annual reports has been fundamentally impacted by the introduction of IFRS. The Reconciliation Statement analysis results reveal that profit disclosed under UK GAAP increased by 105.85 per cent following the implementation of IFRS. In addition, the results show that the introduction of IFRS had a significant impact on reported equity; however, there was an almost even split between those which experienced a favourable impact following the transition and those disclosing a negative effect on the balance sheet post-IFRS adoption. The main IFRS standards which impacted reported results under previous national GAAP were IAS 10, IAS 12, IAS 19, IAS 40 and the IFRS 3/1AS 36/IAS 38 group of standards.The assessmenot f the decision-usefulness of the new IFRS information reveals that the widespread variation in impact on reported results, the complexity of the supplementary narrative disclosures, absence of company-specific and forward-looking information, uncertainty about the long-term impact of the changeover and the lack of comparability between the Reconciliation Statements will likely have constrained the usefulness of the new disclosures for users and therefore their investment decisions. Thus, one of the aims of the standard setters does not seem to have been achieved as users of UK corporate annual reports were not supplied with more useful information about these companies compared to what was previously disclosed under UK GAAP.