The failure rate of Customer Relationship Management (CRM) implementations is estimated to be greater than 65%. Lowering the failure rate and supporting the success of information systems (IS) are the ultimate goals of IS practitioners and researchers. However, most previous research in the area has focused on identifying factors such as critical success factors (CSFs) that are correlated with IS success. There has been little research on how IS implementation may lead to successful results. The state of knowledge in IS implementation may be likened to cooking with a list of ingredients but not the recipe. Drawing on process theory, this study examines the process of IS implementation by explaining how factors of IS implementation influence each other and how interactions among them produce results. Based on one successful case and two unsuccessful cases, we develop the process model of IS implementation, by which the process of IS implementation and the dynamics of IS success can be explained. The proposed model facilitates an understanding of how repeating patterns of IS failure can be reversed, and could serve to guide new IS implementation projects.