In software product family engineering reusable artifacts are produced during domain engineering and applications are built from these artifacts during application engineering. Modeling variability of current and future applications is the key for enabling reuse. The proactive reuse leads to a reduction in development costs and a shorter time to market. Up to now, these benefits have been realized for the constructive development phases, but not for testing. This paper presents the ScenTED technique (Scenario based TEst case Derivation), which aims at reducing effort in product family testing. ScenTED is a model-based, reuse-oriented technique for test case derivation in the system test of software product families. Reuse of test cases is ensured by preserving vari-ability during test case derivation. Thus, concepts known from model-based testing in single system engineering, e.g., coverage metrics, must be adapted. Experiences with our technique gained from an industrial case study are discussed and prototypical tool support is illustrated.