The microwave dielectric properties and the microstructures of (Mg1/2Co1/2)Al2O4 ceramics prepared by conventional solid-state route have been studied. The dielectric constant values (epsilon(r)) saturated at 8.3-8.7. The Q x f values of 4500-107,300 GHz can be obtained when the sintering temperatures are in the range of 1480-1600 degrees C. The temperature coefficient of resonant frequency tau(f) was not sensitive to the sintering temperature. The epsilon(r) value of 8.75, Qxf value of 107,300 GHz, and tau(f) value of -54 ppm degrees C-1 were obtained for (Mg1/2Co1/2)Al2O4 ceramics sintered at 1600 degrees C for 4 h. For applications of high selective microwave ceramic resonator, filter and antenna, (Mg1/2Co1/2)Al2O4 is proposed as suitable material candidate. (C) 2011 Elsevier B.V. All rights reserved.