In the recent past, a relevant effort has been devoted to the definition of process modeling languages (PMLs). The resulting languages and environments -although technically successful- did not receive much attention from industry. On the contrary, researchers and practitioners have recently started experimenting with the usage of UML as a PML. Being so popular and widely used, UML has an important competitive advantage compared to any specialized PML. However, it has also a main limitation. While most PMLs are executable by some process engine, UML was conceived as a non-executable, semi-formal language. The work described here aims at assessing the possibility of employing a subset of UML as an executable PML. The article proposes a formalization of the semantics of the UML subset and presents the translation of UML process models into code, which can be enacted in the OPSS process-centered environment. The paper also presents a case study to validate the approach. We expect that process modeling by means of UML is easier and available to a larger community of software process managers. Moreover, process enactment makes the process more efficient, reliable, predictable and controllable, as widely shown by previous research.