The reactive sintering of manganese zinc ferrite has been studied using powders prereacted at 600 degrees C, 900 degrees C, and 1200 degrees C. The results show that the calcination temperature has a pronounced influence on the microstructure evolution during sintering. The selfsintering of iron oxide during the heating of MnZn ferrite compacts prepared from prereacted mixtures, shifts the chemical reaction of MnZn ferrite formation to higher temperatures where the final microstructure is developed.