This paper describes an approach and a tool for test-ing workflows defined in Microsoft’s Workflow Founda-tion (MS-WF). As an integrative part of the Microsoft-.net 3.0 framework MS-WF was widely accepted as one of the major workflow development tool kits and finds rich industrial application [1]. Lacking testing-facilities in MS-WF and the big demand for testing business critical workflows led to the development of ‘Workflow-Inspector (WI), a tool enhancing MS-WF with end-user applicable test-facilities. WI is a joint project among the University of Innsbruck and Telekom Austria.