One of the primary duties of the depositary banks is to protect themselves against any possibility of bankruptcy. This requires the identification and measurement of risks, including default risk, which is important given the nature of the activities of banks. This paper presents an empirical investigation to study the relationship between default probability and some financial figures including operating cash flow, liabilities and return of equities. The proposed study of this paper uses historical data of twenty-two firms listed on Tehran Stock Exchange over the period 2008-2012. Default probability as the dependent variable is measured by the method developed by Moody’s KMV Company. The study uses linear regression model to examine the relationship between default probability and some independent variables. The results of the present study suggest that there were some reverse relationship between operating cash flow per share, return on equities and default probability. In addition, there was a direct relationship between log facilities and default probability. However, there was not any relationship between net sales and default probability.