Objective: Companies’ managements have various resources and different methods of financing at their disposal to provide required cash for capital expenses and company operations. The main purpose of this research is investigating the relationship between capital structure and financing in Corporations. Methodology: Statistical sample size of the research included 147 Corporations of Accepted in Tehran Stock Exchange between 2009 and 2015 (A 7-year period). To test the hypotheses of the research we used panel data method. Results: Research findings show that financial leverage and internal and external financing have a positive and direct relationship. Conclusion: Despite this, findings show a direct and significant relationship of capital structure and reverse and significant relationship of internal and external financing in active companies in Iran`s capital market.