The audit committee effectiveness (ACE) has been researched for several times by academics in accounting and finance literature in terms of relationships with earnings management, corporate governance mechanism, power types and, audit fee etc. This study aims to measure of the emphasize of effective audit committees (ACs) on bank performance via using some of the main bank performance indicators which are return on asset (ROA), return on equity (ROE) and net interest margin (NIM) in the Turkish and the UK banks during 2006-2010.