This study uses financial statements on several hundred companies listed in the Korea Stock Market to analyze trends in inventory turnover ratios and examine the effect of inventory performance on the profitability of the companies. Statistical analyses are done to determine if there have been significant changes in inventory turnover ratios and how turnover ratio pattern varied by factors such as industry, size of the firm, and the effectiveness of previous inventory management. Inventory turnover ratios decreased for four consecutive years and were found to vary by industry. Also it is proved that there was statistically significant relationship between the size of the firm and the average level of inventory as a fraction of sales. Regression analysis is done to investigate the relationship between the inventory management performance and profitability of companies and it is found that improvement in inventory level affected profitability of the companies.