Ceramics in the system (1-x)ZrTi2O6-xZnNb(2)O(6) (for 0.1 <= x <= 0.85) have been prepared by the mixed oxide route; specimens fired in oxygen at 1260 degrees-1300 degrees C achieved 97% theoretical density for most compositions. X-ray diffraction analysis confirmed the co-existence of a disordered alpha-PbO2-type structured phase and a rutile-structured second phase for 0.1 <= x <= 0.25, a single phase having a disordered alpha-PbO2-type structure for 0.3 <= x <= 0.7, and a columbite-type structured phase for x >= 0.85. Wavelength dispersive spectroscopy (WDS) revealed that the TiO2-rich second phase contained significant amounts of ZrO2, Nb2O5, and ZnO. In the two-phase region relative permittivities (epsilon(r)) are predominantly in the range 39-47 (with a peak at x = 0.24), quality factor (Q x f) values peak at 34000 GHz, and temperature coefficient of resonant frequency (tau(f)) decreases with increase in ZnNb2O6 content and tune through zero at x = 0.24. In the single-phase alpha-PbO2 region epsilon(r) decreases, Q x f increases to 49000 GHz and tau(f) decreases to -58 ppm/degrees C with increasing ZnNb2O6. In the ordered columbite structure region (x > 0.85) the epsilon(r) falls to 28, Q x f increases to 59000 GRz and tau(f) is more positive (-20 ppm/degrees C). Ceramics with x = 0.24 exhibited an excellent combination of properties: epsilon(r) = 47, Q x f = 34 000 GHz, and tau(f)similar to 0 PPM/degrees C.