Abstract. Business process models, often modelled using graphical languages like UML, serve as a base for communication between the stakeholders in the software development process. To fulfill this purpose, they should be easy to understand and easy to maintain. For this reason, it is useful to have measures that can give us some information about understandability and maintainability of a business process model. Such measures should tell us whether the model has an appropriate size, is clearly structured, easy to comprehend and partitioned into modules in a sensible way. This paper discusses how existing research results on the complexity of software can be extended in order to analyze the complexity of business process models.