This research investigated how FCF and AC influence performance of the companies listed on Tehran Stock Exchange. Therefore, the main purpose of this study, specifically, is to examine the free cash flows hypothesis, and to test the agency theory. To accomplish this objective, two main hypotheses and eight sub-hypotheses have been developed and tested in 92 companies among the companies listed on Tehran Stock Exchange for 10-years, from 1380 to 1389. “Panel Data” is used as the statistical method to test the hypotheses. In this study, to measure the performance of the company two criteria based on accounting information, return on assets and return on equity, and also, two criteria based on market information, Tobin Q ratio and stock returns are used. The results of analyzing research hypothesis show that, free cash flows have a significant positive relationship with all performance evaluation criteria. So, this study found evidence about the lack of free cash flows hypothesis. Nevertheless, there was no significant relationship between agency costs and firm performance in order to confirm the agency theory in Tehran Stock Exchange.