Most IS projects today are not greenfield projects, but relate heavily to existing information infrastructures and business processes. How should the development process integrate with the business process? This is a crucial question, because a project that does not integrate with the business processes will be a failure, even if the software which is produced is well designed and programmed.

The Software Engineering community has embraced iterative process frameworks, like the Rational Unified Process. These frameworks claim to support a step-wise integration of the business process and the development process.

This paper explores and analyses the managerial challenges of integration in such projects. Building on a longitudinal case study and an analysis of the Rational Unified process, four types of integration are identified and analyzed: External and internal stakeholder integration, and internal and external technical integration. Finding that the external integration mechanisms are just as critical at the internal, the paper concludes that the integration challenge is complex, partly outside the control of the project manager and not supported sufficiently in the RUP framework. A theory extension to RUP is suggested.