CuO-BaO mixtures (molar ratio, CuO/BaO = 1, 2, 2.5) at the 1 wt% level were added to BaTi1+xO3+2x (-0.01 less than or equal to X less than or equal to 0.02) ceramics as a liquid phase promoter to investigate the grain growth of BaTi1+xO3+2x ceramics. Sintering in air for 2 h at 950 to 1250 degrees C was investigated to study the densification process, whereas sintering in air for 1 to 16 h at 1150 to 1250 degrees C was investigated to study the grain growth. The sintered grain morphologies (small grain growth, abnormal grain growth, and normal grain growth) of BaTi1+xO3+2x ceramics depend on the TiO2/BaO ratio, the sintering temperature and time, and the CuO/BaO ratio, slightly. The average grain size increased with the sintering time and temperature. Grain growth is discussed in terms of the kinetic growth equation : G(n) - G(o)(n) = K-o t exp(-Q/RT). It was found that the preexponential, the grain growth exponents, and the activation energies of the BaTi1+xO3+2x system are all dependent on the CuO/BaO ratio, the sintering temperature, and the TiO2/BaO ratio. In the BaTi1+xO3+2x/CuO-BaO system, the average n values are in the range of 4.1 to 7.6, and the activation energies are in the range of 109 +/- 30 to 1007 + 180.