Earnings management via discretionary accruals is a manager's instrument for changing stock holders’ expectations. The purpose of this study is to investigate the role of discretionary accruals in the earnings management of Iranian firms. There are two hypotheses associated with this study on the relationship between income smoothness and discretionary accruals and the proposed study is implemented on selected firms from Tehran Stock Exchange. The result of the first hypothesis indicates the relationship between earnings smoothness and discretionary accruals variables. It means that discretionary accruals (DA) leads to the converse relationship among discretionary accruals variation and current and future cash flow. The result of the second hypothesis indicates that the firms with high variation in Iran utilize more discretionary accruals compared with the firms with lower variation.