" This study investigates the relationship between corporate social responsibility disclosure level and cost of capital for both of (cost of equity, cost of debt) of the company using a sample of 70 Egyptian listed companies from different sectors with a period of 6 years (2013-2018). Corporate social responsibility disclosure level was measured by an unweighted disclosure index that was developed and consisting of 31 items and divided into 4 dimensions of social responsibility (employees, society, environment, customers).Cost of capital was measured by weighted average cost of capital (WACC) ,cost of equity was measured using (Easton, 2004) model not (CAPM) due to its lack of suitability for the Egyptian environment due to its assumption of the efficiency of the market, and cost of debt was measured according to Egyptian Accounting Standard No.14 by debt interest rate after consideration the tax impact. The researcher used one lag period time and three lag periods in the empirical study. The results provide evidence that there was a negative and significant relationship between corporate social responsibility disclosure level and cost of capital for both of (cost of equity, cost of debt) using three lag periods of time. While there was no significant relationship between variables using one lag period time except cost of debt. This negative relationship between corporate social responsibility disclosure level and cost of capital depends mainly on lag period time that companies need to reflect the impact of this type of disclosure on the shares of these companies under the awareness of investors of the importance of this type of disclosure and that profit is not the only standard when making investment decisions, but social responsibility dimensions must be considered. The main responsibility of the company is the social responsibility if it wants to stay and continue for the long term. "