Relative ability to reduce or increase of reported earnings by managers are introduced as manipulation of accounts. Topics such as maximizing, minimizing, or smoothly refers to who implicitly take action to manipulated of accounts. Of course manipulation of accounts be encompasses considerably broader scope. Accruals are defined as distance between operating cash flows and accounting profit. Earnings management is intentional interference in external financial reporting process with intent to obtain a benefit. Income smoothing has two forms: 1- Reduction of Earnings; It is when the expected profit will be high temporarily, 2- Incremental Earnings; It is when profits will be lower than expected profit or profits of the previous year. In this article explains to importance of accruals, earnings management, earnings management utility, income smoothing and the role that play in the accounting.