In this paper we address the concept of business architecture. We explain the concept and, based on a case study, discuss its relevance, operation, relationship with strategy and business models, and value for an organization. Business architectures contribute to clarify the complexity within an organization and form a useful starting point from which to develop functional, information, process and application architectures. In addition, an explicit business architecture helps to structure the responsibilities within an organization, and to shape outsourcing activities, within the primary process as well as with regard to ICT-support. Business architectures contribute to an adequate ICTgovernance in order to orchestrate the resources for critical business activities and how to manage the development and support for e-business efficiently.