Calcium zirconate (CaZrO3, CZ) was prepared using a solid-state reaction with mechanochemical activation through vibro-milling, aiming at completing the reaction CaO+ZrO2=CaZrO3 at relatively low calcination temperatures. Changes in the crystallite size and homogeneity of the mixed components CaO and ZrO2 in the starting mixtures were observed with different milling times. The influence of milling on the incipient temperature of CZ formation and completion of CZ formation was investigated. It is concluded that milling of the reactants for 20 h lowered the incipient temperature of CZ formation from 800 degrees to 600 degrees C, and the temperature of complete CZ formation from above 1100 degrees to 800 degrees C.