Abstract. Business process models describe workflows by a set of actions together with their ordering. When implementing business processes within a service-oriented architecture, these actions are mapped to existing IT (web) services, which are then to be executed in the order specified by the business process. However, the execution of a web service can require certain preconditions to be fulfilled. These might not hold at the time of execution specified in the business process model: it can be inconsistent with the web service specification. In this paper we propose a technique for checking consistency of process models with web service specifications. To this end, both are equipped with a formal semantics (in terms of graph transformations). We show how to use an existing model checker for graph transformation systems to carry out the consistency check. Key words: Business processes, web services, UML Activities, visual contracts, graph transformations