Service-oriented architecture (SOA) have been adopted by organizations in a wide variety of industries, however, best practices have still yet to mature. This article, which is part of a larger study on SOA, develops a normative decision model introducing key factors that influence the timing and approach of adopting a SOA. The decision model is based on the results of multiple case studies of organizations that had either employed or were considering implementing a service-oriented architecture project. The results indicate that there are four main areas an information technology (IT) manager needs to assess to determine when and how to move towards a SOA: the maturity of relevant standards, the technology gap, the organizational gap, and the nature of the benefits expected from a SOA. Analyzing these results suggest that differences in the business environment need to be considered in the decision of when and how an IT manager should pursue the move to a service-oriented architecture.