Graphite-fiber-reinforced magnesium (Gr/Mg) composite materials offer an excellent combination of high strength and stiffness at both ambient and elevated temperatures, light weight, good fatigue and damping characteristics, and high thermal conductivity. Material Concepts, Inc. (MCI) has developed a method of casting these materials to near net shape. Under a two-phase program sponsored by NASA Lewis Research Center, MCI is developing the technology for producing rotary engine components from Gr/Mg. In the preliminary phase, the feasibility of casting a generic intermediate housing was demonstrated. In the current phase, the goal is the fabrication and performance testing of a rotor housing. CAD techniques will be used to determine optimum fiber orientations for mechanical and thermal performance; methods of applying a suitable trochoid wear surface will be developed; and advancements in the casting and NDE technology will result in the production of commercial quality cast components.