This study explores some questions which few researches are involved in our knowledge, but they trouble the managers of the case study. Basing on the approach of information process, this study aims to contribute to Activity-Based Costing literature by linking the relationship between Activity-Based Costing and managerial decisions of market orientation. Besides, this study also contributes to the firm practical operating by applying the philosophy of market orientation to ABC system implementation. In summary, this study focuses on how Activity-Based Costing information could use to response a special order, reduce inter-departmental conflicts, and manage the customer relationships. The case study in a high-tech industry is provided to illustrate the potential for improving managerial decision of market orientation when Activity-Based Costing system is utilized versus traditional accounting systems.