This paper describes an ongoing research project, funded by the Ee Esprit program, aiming at developing a software workbench supporting the manufacturing systems engineering process. The system provides a user-friendly and powerful environment in which tools supporting the conception, design and evaluation of manufacturing systems will be integrated in a common framework. The foundation of the workbench is a descriptive method of the domain of manufacturing systems (based on the object-oriented methodology), enabling the description of all the aspects of a generic manufacturing system. The paper describes the main design issues of the workbench and presents its logical architecture; then it underlines how this system can allow the coordinated work of many design teams of a distributed company thanks to the standard descriptive method used to describe manufacturing systems. It is possible to foresee that such a system could have a dramatic impact on the manufacturing system engineering process in the extended enterprise environment.