The present study examines the relationship between efficiency index of working capital management and efficiency of assets in four industries. The efficiency of working capital management is one of the main prerequisites of success in a commercial unit and it is defined as managing the working capital in a way that sufficient amounts of working capital are used in order to stabilize the firm and obtain profitability and cash. In the current study, in order to determine the efficacy of working capital management four indexes have been used, including Performance Index of Working Capital Management (PIWCM), Utilization Index of Working Capital Management (UIWCM), Efficiency Index of Working Capital Management (EIWCM), Cash Conversion Cycle (CCC) the conventional financial ratio of determining the efficacy of working capital management, and the dependent variable is the efficiency of assets. The statistical samples of the study are the firms accepted in pharmaceutical, chemical, base metal and non-metal mineral industries, and a total number of 72 firms were selected as the sample. Regression method of analysis was employed to analyze the data. The result of this study is different in industry level of the industries under investigation and the total number of the firms studied. However, among efficiency indexes of working capital management and cash conversion cycle, the efficiency index was selected as the optimal index related to determining the efficiency of the assets.