Over the past decade, the European Commission, as the institution responsible for implementing the Community Budget, has taken an increasingly active interest in the effectiveness of the control measures applied by Member States to Community funds. Indeed, it is in the common interest of the Member States to exercise proper supervision of Community funds. The responses of EU Member States’ Supreme Audit Institutions (SAIs) to the Commission’s external audit procedures and requirements are divergent for various reasons, including legislative ones. This issue overview paper draws on the separate country papers which describe in more detail the different experiences of selected national SAIs in their co-operation with the Commission’s services and the European Court of Auditors (ECA). The present publication complements SIGMA Paper No. 19 Effects of European Union Accession — Part 1, Budgeting and Financial Control on the impact of accession on budgeting and financial control. In both cases, the approach adopted has been analysis of selected issues for reflection and debate.