This paper presents an ontology-driven approach that aims at supporting semantic verification of semi-formal process models. Despite the widespread use of these models in research and practice, the verification of process model information is still a challenging issue. We suggest an ontology-driven approach making use of background knowledge encoded in formal ontologies and rules. In the first step, we develop a model for ontology-based representation of process models. In the second step, we use this model in conjunction with rules and machine reasoning for process model verification. We apply our approach using real-life administrative process models taken from a capital city.