Cooperative Product Development is the principal mechanism for supporting Concurrent Engineering. In large organizations, cooperative product development is expected to take place with the involvement of teams of geographically separated product developers working in a distributed and heterogeneous computer environment. Communication, cooperation, and coordination are essential for cooperative product development by members of a product development team virtually co-located over a network. The coordination framework in a computer-based cooperative product development environment is responsible for communicating work, securing focus, and ensuring progress towards a goal. A necessary function of the coordination framework, provided by a Constraint Management System, is the ability to capture and manage the constraints in the product development process. The development of a prototype Constraint Management System is discussed in this paper. The requirements of a Constraint Management System are specified and further work in constraint management, in the context of applications to product development, is outlined.