In response to declining prices IT service providers seek to reduce costs by achieving greater economies of scale. The divergent requirements of corporate customers, however, limit the opportunity to achieve scale economies through standardization of services. In response, some outsourcing vendors have embraced a strategy of employing reusable service modules match their clients' needs. Reusable modules create room for standardization on the component level while maintaining the ability of the provider to tailor offerings to individual requirements. In this paper we introduce a method for identifying reusable service modules and demonstrate their application based on case study at a leading European IT Service Provider. The paper discusses the implications of embracing modularization for service offerings and service management.