There are substantial evidences that managers engage in earnings management. Alternative measurement rules and the need for judgment in applying generally accepted accounting principles(GAAP) result in opportunities for managers to manipulate earnings. According to Healy and Wahlen(1999), ‘‘Earnings management occurs when managers use judgment in financial reporting and in structuring transactions to alter financial reports to either mislead some stakeholders about the underlying economic performance of the company or to influence contractual outcomes that depend on reported accounting practices.’’A number of studies discuss the probability that intentional intervention in the financial reporting can occur not only through accounting methods, but also through operational decisions. Bushee(1998) and Healy and Wahlen(1999) point to acceleration of sales, alterations in shipment schedules, and delaying of research and development(R&D) and maintenance expenditures as earnings management methods available to managers. Specifically, Roychowdhury(2006) finds evidence suggesting price discounts to temporarily increase sales, overproduction to report lower cost of goods sold, and reduction of discretionary expenditures to improve reported margins. Under these circumstances, this study is concerned about whether the change of inventory levels involve earnings management. Manufacturing firms can manipulate income by producing in excess of the quantity needed to meet current period demand, thereby allocating part of current period fixed manufacturing overhead costs from cost of goods sold to inventory. Manufacturing firms can modify inventory levels to adjust cost of goods sold through absorption costing mechanics for fixed production costs. This paper is to provide evidence that manufacturing firms manipulate inventory levels to manage earnings. It is possible that manufacturing firms may manipulate income by producing in excess of the quantity needed to meet current period demand. To examine the relation between the changing of inventory levels and earnings management objectives, this paper sets the hypothesis, “Abnormal increasing of inventory levels are involved in the earnings management”. This paper estimates the discretionary accruals(DA) as earnings management variables with the modified Jones(1995) model. And the changing of inventory levels(CI) are defined as the differences between change of inventory and cost of goods sold from the previous period(t-1) to the current period(t) designed by Jiambalvo et al.(1997) or Rosner(2003). The test sample consists of 3,327 firm-year data, selected from the Korea Stock Exchange(KSE) listed companies during the year 1999-2007. The major findings of the study are as follows:First, the correlation coefficient between CI and DA is positively significant at under 1%level (p < 0.001). This means the more the managers adjust the changing of inventory levels, the higher earnings management is done. Secondly, abnormal increasing or decreasing of inventory levels is positively related to discretionary accruals. It is natural that managers should forecast the future sales, inventory levels are accompanied. However, when managers goes wrong with the future sales, abnormal increasing or decreasing of inventory levels may be involved in earnings management. The results suggest that the earnings are managed or over-managed through the increasing change of inventory levels, regardless of usual future sales, which is consistent with the hypothesis.