Ca(Zn1/3Nb2/3)O-3 microwave dielectric ceramics were prepared using a solid-state reaction process, and their microwave dielectric properties were evaluated as functions of sintering and postdensification annealing conditions. The relationship between microwave dielectric properties and processing was interpreted through the variation of microstructures. The dielectric constant showed slight variation with sintering and annealing conditions, but the QxF value increased at first and then decreased with increased sintering temperature, and annealing in oxygen indicated significant improvement in QxF, especially for the specimens sintered at higher temperatures. The good microwave dielectric properties were obtained in the ceramics sintered at 1225degreesC in air for 3 h and annealed at 1100degreesC in oxygen for 8 h: epsilon = 34.1, QxF = 15 890 GHz, tau(f) = -48 ppm/degreesC.