Our ongoing work aims at defining an ontology-centered approach for building expertise models for the CommonKADS methodology. This approach (which is named "OntoKADS") is founded on a core problem-solving ontology which distinguishes between two conceptualization levels: i) at an object level, a set of concepts enable us to define classes of problem-solving situations. This sub-ontology extends the foundational ontology DOLCE [3]; ii) at a meta level, a set of meta-concepts represent modeling primitives. In particular, a set of such meta-concepts render an account of roles, the primitive situated at the interface between domain knowledge and reasoning, and whose ontological status is still much debated since the late 1990s [5]. In this short article we give an overview of OntoKADS. Categories and Subject Descriptors I.2.4 [Artificial Intelligence]: Knowledge Representation Formalisms and Methods General Terms: Theory. Keywords Knowledge Engineering and Modeling methodologies...