Abstract. In this paper we present a novel approach for the predicative specification of user rights in the context of an object oriented use case driven development process. We extend the specification of methods by a permission section describing the right of some actor to call the method of an object. Moreover, we introduce a representation function that describes how actors are represented internally in the system. As syntactic and semantic framework we use a first-order logic with a builtin notion of objects and classes provided with an algebraic semantics. We demonstrate that our approach can be realised in OCL.