The Boeing Company has pursued the development of an open, software reference architecture for vehicle health management (VHM) systems. Boeing's role as a system integrator has motivated this effort to reduce the development and integration cost of VHM systems and to achieve a higher level of performance that includes totally integrated diagnostics and prognostic capabilities. The development of this architecture was begun by an industry consortium lead by Boeing under a Navy Dual Use Science and Technology Program. This program was entitled open system architecture for condition based maintenance (OSACBM), and it has been continued under the auspices of the machinery information management open systems alliance (MIMOSA). The rewards and challenges of introducing this VRM open architecture into the system development and business processes are described.