—In this paper, we present a UML metamodel-based approach for creating and executing workflow models. The modeling language is introduced through its abstract syntax, and an evaluation shows how this language supports known workflow patterns. Some patterns can be expressed easier compared to established languages like EPCs or BPMN. Organizational and data aspects in workflow models can be described on the basis of the presented metamodel. The workflow models can be instantiated and executed with a tool realizing parts of the UML action semantics. At an early stage of design, our workflow models can be evaluated by testing scenarios with the used tool in combination with the developed workflow plugin. Employing the tool, dynamic aspects of the workflow process models together with data and organizational aspects can be evaluated. During execution of the workflow scenarios, the workflow models can be adaptively changed, and data can be captured and evaluated by formulating process mini...