This study aims to investigate benefits of implementation of an ERP system. Many previous studies concerning ERP either focused on key successful factors (KSF) of implementing an ERP or benefits of implementing a particular ERP module. In practice, however, the overall benefits of an ERP system for the company are the most concerned. In this paper, a case study method is employed to investigate benefits of implementation of an ERP system. Both the interview and the online questionnaire survey are used. The case company-K-company specializes in the IC assembly. Its ERP system is ”Workflow,” a product from DATA SYSTEM Company, which is one of the most famous and top ERP suppliers in Taiwan. Our main findings are as follows: 1. The inventory accuracy increases as operators are more familiar with the ERP system. 2. As the routine operations completed by the ERP system increase, the timeliness of inventory data can be enhanced. 3. The amount of account receivable can be decreased after implementing the ERP system. 4. The monthly settlement can be completed within 10 days after implementation of ERP, while it needs 20 days before implementation.