Abstract: The main purpose of this study was to evaluate the sensitivity of financing, through debt and the sale of shares in free cash flow is under financial constraints. Sensitive sources of financing to the company’s cash flow is an issue that has received considerable attention in recent decades. The sources of financing sensitivity of cash flows, cash stretch sources of financing or the percent change in the sources of financing to changes in cash flows of the company. In this study, the cash flow generated inside the company as the first strategy chosen financing and debt and equity, respectively next priorities, funding was elected. The research from the perspective of objective research, applied research, Methods on how to apply is that the data related to the calculation and measurement of variables related to the model, Exchange databases and software obtaining new rahavard and then calculating the variables using the techniques of descriptive and inferential statistics, the variables were analyzed and tested hypotheses. The study based on the data type, a quantitative. The population consisted of 112 companies of all listed companies in Tehran Stock Exchange in the period 2009-2013. The results of the test hypotheses of this study showed that between that the financing through debt and free cash flow in companies with financial constraints, there is a significant and negative relationship and between the financing through the sale of shares and free cash flow in companies with financial constraints, there is a significant and negative relationship. The results showed that a strong long-term relationship between the variables there.