In this paper, we propose an approach for the recovery of service abstractions out of sets of available services that play the role of alternative design-decisions, which can be used in a service-oriented application. A service abstraction provides a uniform interface that hides dierences in the interfaces of alternative services and consequently allows reducing the coupling between the application and the services. To this end, we formally define the notion of service abstraction and propose a hierarchical clustering algorithm that incrementally recovers a hierarchy of service abstractions out of a given set of alternative design-decisions/services. Finally, we evaluate the proposed algorithm with real-world sets of services and report on our findings.