In this study the relationship between corporate governance and corporate valuation, ownership structure and need of external financing for the Karachi Stock Market is examined for the period 2003 to 2008. To measure the firmlevel governance a rating system is used to evaluate the stringency of a set of governance practices and cover various governance categories: such as board composition, ownership and shareholdings and transparency, disclosure and auditing. The sample consists of 60 non-financial firms listed on Karachi Stock Exchange and comprises more than 80 percent of market capitalization at Karachi Stock Market in 2007. The results confirms the theoretical notion that firms with better investment opportunities and larger in size adopt better corporate governance practice. The proposition that ownership concentration is a response to poor legal protection is also validated by the results. The more investment opportunities lead to more concentration of ownership and the ownership concentration is significantly diluted as the firm size expands. The findings are consistent with theoretical argument claiming that family owners, foreign owners and bring better governance and monitoring practices which is consistent with agency theory. The results suggest that firms which need more equity financing practice good governance. The results show that firms with high growth and large in size are in more need of external finance. The relationship between external financing and ownership concentration is negative. The results reveal that the firms which practice good governance, with concentrated ownership, need more external finance which have more profitable investment opportunities and are larger in size are valued higher. The interaction term of any variable with law enforcement term are not significant in any model suggesting that firm performance is not affected by rule of law in countries where legal environment is weak. These results adds an important link to the explanation of the consequences weak legal environment for external financing, corporate valuation and corporate governance. The results show that Corporate Governance Code 2002 potentially improves the governance and decision making process of firms listed at KSE.