Multimedia presentations are suitable for instruction delivery. In a distance learning environment, multimedia presentations are lecture materials to be broadcasted among a number of workstations connected by networks. In order to manage these course materials efficiently, a multimedia database management system (MDBMS) is essentially important. We propose a MDBMS, which has five layers. Attributes of elements in each layer as well as database operations are discussed. The system supports storage sharing and object reuse. The system is implemented on Windows ’98 with the support from a conventional database management system. Also, we present an instruction-on-demand system, which is an application of the underlying MDBMS. The instruction-on-demand system is used in the realization of several computer science-related courses in our university.