Introduction:Jensen (1986) predicts that when managers maintain more free cash flow in hand, they commit opportunistic behaviors such as investing in projects with fewer net cash, less amount of effort for creating revenues, causing more unnecessary expenses, wasting revenues, and other such things. He also predicts that an increase in financial leverage enforces managers to be more disciplined and would reduce their opportunistic behaviors, because paying debt reduces the free cash flow. On the other hand, establishing debt has influence on free cash flows. Therefore, there is an interaction between risk of free cash flow and establishing a debt. Also there are other factors that influence both of these factors. Consequently, this research tests the efficiency of the ownership structure and the debt policy as a mechanism of resolution of agency conflicts between shareholders and managers due to the problem of overinvestment, and in the limitation of the problem of the free cash flow. In other words, in this study the free cash flow theory of Jensen (1986) with some of relevant variable are investigated.