Accounting conservatism limits managerial incentive and ability to overstate performance and hide bad news from investors, which, in turn, reduces stock price crash risk. This study examines relationship between conservatism on financial reports and risk of stock price crash. Using a sample of 54 listed firms in Tehran Stock Exchange over the period of 2006–2010 and panel logistic regression, we examine different hypotheses. The results indicate that accounting conservatism, as measured by Khan and Watts (2009) CSCORE [Khan, M., & Watts, R. L. (2009). Estimation and empirical properties of a firm-year measure of accounting conservatism. Journal of Accounting and Economics, 48(2), 132-150.], reduces the likelihood of a firm experiencing stock price crashes. The finding holds after controlling other variables such as: negative skewness of firm-specific-weekly return, standard deviation of firm-specific-weekly return, the mean of firm-specific-weekly return, detrend share turnover, size, market to book value of equity ratio, total debt ratio and return on asset ratio, but we did not observe any relationship between these variables during stock price crash.