The relevance of business processes as a major asset of an enterprise is more and more accepted: Business processes prescribe the way in which the resources of an enterprise are used, i.e., they describe how an enterprise will achieve its business goals. Organizations typically prescribe how business processes have to be performed, and they seek information technology that supports these processes. We describe a system that supports the two fundamental aspects of business process management, namely the modeling of processes and their execution. The meta-model of our system deals with models of business processes as weighted, colored, directed graphs of activities; execution is performed by navigation through the graphs according to a well-defined set of rules. The architecture consists of a distributed system with a client/server structure, and stores its data in an object-oriented database system.