Economic development in the era of globalization requires each company to continue to grow and develop. To know the development of an enterprise can be seen from the value of the company. The value can be determined by the company's capital structure. As is well known that the structure of the financial cost of capital is derived from the composition of long-term debt and capital itself. Any changes in capital structure will result in a change in the cost of capital and corporate value. Therefore, companies must try to determine the optimal capital structure to minimize the cost of capital so that the company's value will increase. This study aims to determine how policies affect the company's long-determination of the source of funding or capital structure of the company for three years (2006-2008) and determine if capital structure has been established for three years has been optimized so as to increase the value of the company Research methods used in this study is disriptif research method with type of case study on PT. Semen Gresik (Persero) and its subsidiaries. Analysis performed includes the analysis of profitability ratios, leverage ratios, capital structure analysis, analysis of capital costs, the company value analysis to determine the optimal capital structure. The results of this study indicate that the optimal capital structure in PT. Semen Gresik (Persero) Tbk and Subsidiaries occurred in 2007. This is evidenced by the minimum cost of capital in the amount of 17.13%, while the next two years cost of capital increased sharply in the amount of 18.85% in 2006 and 20.32% in 2008. This capital cost increases due to company policy who prefer using their own capital in fulfillment of the funds so that the composition of long-term debt and capital itself is not balanced. In the year 2008 company's capital structure was not optimal, although the value of a company that achieved increased from previous years in the amount of 12,174,631,490, this is because the company's profits have increased. Therefore, in determining the company's capital structure should be more careful and consider the national economic conditions.