It is assumed in Merger & Acquisitions (M&A) research that there exists a relationship between business and IS aspects. However, research and literature explicitly addressing the relationship between both is scarce. In this paper we introduce a model to understand the aspects that play a role in an integration process. We focus on process factors and effects, both from the business and IS domain, in particular we are focusing on their interaction. Two cases in the transport industry are presented and discussed. The research discusses the validity of recurring integration process factors and effects, but also indicates the relevance of contextual aspects. The research contributes both to M&A research as well as to IS research by increasing the understanding of factors that impact integration processes and by that it gives direction how these factors should be managed.