The main objective of this study is to investigate the relationship between monetary policies, capital structure and risk-taking of listed banks in Tehran Stock Exchange. In this study, to measure the monetary policies, the indicator of legal reserve rate have been used. The sample consists of 21 banks listed in Tehran Stock Exchange in the period from 2012 to 2018. In this study, the data were extracted from the Rahavard Novin 3 software and then classified by Excel software, and after calculating the variables, finally, through Eviews10 software, the multivariable regression model and panel data was used to test the hypotheses. The results showed that there is significant negative relationship between monetary policies and banks' risk-taking with in 95% confidence level. In addition, other findings indicated existence of a significant positive relationship between monetary policies and bank capital structure. However, the research results show that there is no significant relationship between bank capital structure and banks' risk-taking.