This study aims to examine the effect of internal control system for inventory on the reasonableness of inventory management at Makro Supermarket and Department Store Gorontalo, both simultaneously and partially. The primary data are collected through a list of statements/questions. Each item of the statement/question contained in the list is examined using validity and reliability test. The analytical method applies Path Analysis by initially converting the data of ordinal scale into interval scale. The object of this study is the application of the internal control system for inventory and the reasonableness of inventory management. The result of the hypothesis indicates that the internal control system for inventory (X) which consists of good receipt procedure (X1), warehouse procedure (X2), and goods release procedure (X3) simultaneously has a positive and significant effect of 97.8% on the reasonableness of inventory management (Y) at Makro Supermarket and Department Store. The remaining 2.2% is from other variables which are not examined in the research model.