The agency- and stewardship theory attach great importance to the implementation of audit committees in the one tier- and two tier system. The mentioned theories can explain the corporate governance function of audit committees. In order to strengthen corporate governance, the job specification emphasises the independence and financial expertise of the committee’s members. The present article provides an overview of the historical development of audit committees and their normative affiliation in the German stock corporation law (two tier system). Moreover, their role as representatives of the one tier system in the US American capital market is being addressed. The results suggest more restrictive standards regarding the implementation and job specification of the audit committee at the US stock exchange (Sarbanes Oxley Act; New York Stock Exchange [NYSE], National Association of Securities Dealers Automated Quotations [NASDAQ]) than in the German stock corporation law (including the German corporate governance code). In addition to the normative analysis, the present paper provides a summary of results of existing, primarily US American empirical research with regard to the influence of audit committees on selected corporate governance indicators. The results show that the vast majority of the respective studies prove a significant correlation between audit committees and the restriction of earnings management, the identification and prevention of management failures and fraud with regard to the balance sheet, the external management reporting as well as the quality of the external audit. As a consequence of differing corporate governance systems, the results of the US American corporate governance studies can be applied only to a limited extend to the German two tier system. Monitoring by the capital market is even lower in Germany. In support of the respective empirical results and in order to strengthen corporate governance in the one tier system, future research is needed regarding the implementation of audit committees in the German two tier system.