Ferrimagnetic materials for microwave applications are reviewed with emphasis on the more recent advances. Specific areas of discussion include temperature sensitivity of the magnetization, microwave loss phenomena and the concept of effective linewidth, and the hysteresis loop in terms of the factors which influence its coercive force, remanence ratio, and stress sensitivity. The relations between specific chemical substitutions and the attendant magnetic properties are then summarized for the various spinel and garnet ferrite families of interest to the microwave device engineer. Finally, the ceramic preparation of ferrite materials is outlined with special focus on some of the newer techniques.