The effects of microwave calcination (MC) and conventional muffle furnace calcination (CC) on the microstructure and magnetic properties of M-type hexagonal ferrite Ca0.15La0.39Sr0.46Fe11.7Co0.3O19 were investigated. The phase composition, microstructure, and magnetic properties of calcined materials were examined using X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometry. Experiments indicated that the MC method can achieve both pure phase, and fine and uniform grains for both calcined and sintered M-type hexaferrites. MC treatments resulted in a magnetization at 15kOe of 67emu/g and an increase in coercivity by 12% over the CC technique. The improved magnetic properties resulting from microwave-assisted calcination were attributed to the formation of a fine-grained morphology, which yielded a narrow grain size distribution. The microwave calcinating technique was shown here to possess unique potential for fabrication of high-performance ferrites and possibly other ceramics.