This paper investigates the role of corporate disclosure policy on risk assessment and market value on selected firms from Tehran Stock Exchange over the period 2004-2012. The study considers four risk namely; business risk, cash flow risk, financial risk and systemic risk. Using regression analysis with panel data under fixed effect, the study shows that there was a meaningful relationship between two risks, business risk and systematic risk, and market value before and after corporate disclosure. In other words, after corporate disclosure, the relationship between risk and market value becomes stronger.