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.