The main objectives of this study are (1) to identify the conflict types in IS integration process with respect to M&A, (2) to propose the ways to manage the origin of conflict to be expected, and (3) to develop the conflict management model which establishes the relationship among the M&A strategy, the IS integration strategy and change management process that influence the source of conflict. In order to achieve these research objectives, this study focuses on banking industry under M&A with the viewpoint of change management instead of existing technology-oriented IS integration strategy. The findings of this study are thought not only to be useful as a practical guideline in carrying out IS integration project under M&A but also to provide significant basis for constructing the theoretical framework of effective IS integration strategy.