Abstract. The importance of modelling the dynamic architectural characteristics of software systems has long been recognised. However, the nature of the dynamic architectural characteristics of service-oriented applications goes beyond what is currently addressed by existing architecture description languages (ADLs). At the heart of the service-oriented approach is the logical separation of service need from the need-fulfillment mechanism, i.e., the service provider: the binding between the two is deferred to runtime and established at the instance level, i.e. each time the need for the service emerges. In this paper we present an architecture-oriented model for dynamic reconfiguration that paves the way for the definition of ADLs that are able to address the specification of dynamic architectural characteristics of service-oriented applications.