The low-temperature sintering of BaTiO 3 (BT) ceramics was investigated by conventional ceramics processing using a CuBi 2 O 4 sintering aid, and the dielectric properties and microstructures of the ceramics were examined. BT powders without CuBi 2 O 4 could not be fully densified at sintering temperatures lower than 1300 C. However, the addition of CuBi 2 O 4 markedly enhanced the sinterbility of BT powders, and the sintering temperature decreased from 1300 to 920 C. This may be due to the promotion of liquid-phase sintering. 6.0 wt % CuBi 2 O 4 -added BT ceramics sintered at 920 C exhibited a high density of 5.95 g/cm 3 . Moreover, to obtain dielectric ceramics with a stable temperature coefficient of capacitance, the effects of ZnO addition on the dielectric properties and microstructures of low-temperature-sintered BT ceramics with a CuBi 2 O 4 sintering aid were also studied. It was found that the addition of ZnO was very effective for improving the temperature coefficient of capacitance and reducing the dielectric loss of the low-temperature-sintered specimens. This is attributable to the microstructural change involving the formation of a core-shell structure, as shown by transmission electron microscopy and X-ray energy-dispersive spectrometry (TEM-EDS). Therefore, a high dielectric constant of 1900, a low dielectric loss of 0.6% and a stable temperature coefficient of capacitance (X7R EIA standard of ÁC=C 25 C ¼ AE15% in the temperature range from À55 to þ125 C) were obtained for 1.0 wt % ZnO-added BT ceramics with 6.0 wt % CuBi 2 O 4 sintered at 930 C for 2 h.