The purpose of this study is to examine the effectiveness of audit committee in constraining earnings management after the revised MCCG among listed firms on Bursa Malaysia. Specifically, the study explores how audit committee impacted earnings management before and after the revision of MCCG in 2007. This study is important because it is among the pioneer empirical evidences to compare the effectiveness of audit committee characteristics in mitigating earnings management between the pre and post revised MCCG periods. The sample for this study was drawn from 280 companies listed on Bursa Malaysia in 2005, 2006, 2008 and 2009. The audit committee characteristics include size, independence, expertise, frequency of meetings and activity disclosure. The discretionary accrual was estimated using the Modified Jones Model (1995) which was used to proxy for earnings management. The empirical results on audit committees play an important and effective role in reducing earnings management after the revision of MCCG. After controlling for firm size, board size and leverage, the study found that audit committee size and audit committee that had meetings with external auditor without the presence of executive directors at least twice a year showed a significant association with earnings management. Overall, these findings called for further examination into the roles of audit committee in mitigating earnings management. Key Words: Audit committee, earnings management, expertise, activity disclosure, Malaysian Code of Corporate Governance (MCCG).