A service-oriented architecture (SOA) promises a more flexible intra- and interorganizational integration of heterogeneous application systems. The central design element of a SOA consists of services which encapsulate existing application logic, and can be dynamically combined to form business processes. This paper aims at contributing to the emerging discipline of "service engineering" by investigating the design principles for B2B services. The authors draw on an analysis of the literature to derive the main design principles for services and evaluate two alternative design proposals for a concrete application scenario in the automotive industry. The results comprise statements on the quality of the service design in the concrete case as well as an outlook for future topics of research in "service engineering".