| The implementation of Good Corporate Governance (GCG) can be interpreted as a process used by companies to improve the quality of earnings with considering the interest of stakeholders, which based on the applicable norms of laws and regulations. This study aims to determine the effect of the implementation of Good Corporate Governance (GCG) with Board of Commissioners size indicator, the proportion of Independent Commissioners, and the Audit Committee of the company’s financial performance as measured by Return on Assets (ROA), Return on Equity (ROE), and Net Profit Margin (NPM). The research method is multiple linear regression analysis using SPSS 13.0. The object of this research is manufacturing company listed in Indonesia Stock Exchange (IDX) in the period of 2009-2010. The results of the research show that GCG has a positive effect on ROA and ROE, but it does not give any impact on NPM. It means a good application of GCG will lead to a good financial performance. This illustrates that the management of the company is aware of the long-term benefits from the implementation of GCG, namely the direct financial impact as an increase in net profit |