Many corporate mergers fail to achieve their intended objectives. The literature indicates that slow post-merger integrations are partly responsible for such failure and highlights that a successful post-merger integration is essential to a successful merger. Recognizing the fact that information systems (IS) integration is important for effective merger performance and that few IS and merger research has addressed this area, the objective of this article is to focus on organizational and information systems factors that affect post-merger IS integration performance with the eventual aim of identifying ways in which to manage the significant factors post-merger. This research is timely and relevant and will contribute to the body of research that facilitates the understanding and management of merger effectiveness and its associated processes.