A slurry method was used to determine the dielectric permittivity (epsilon(r)) of BaTiO3 powders with different characteristics, such as tetragonality (c/a ratio), density, particle size, and specific surface area. The epsilon(r) of powders highly depended on their characteristics. In order to extract the effect of each characteristic, a statistical analysis was carried out to represent the epsilon(r) of powders with an empirical formula. A fairly good agreement was obtained between observed data and those estimated from the formula. The epsilon(r) decreased with particle size because of the size effect of BaTiO3 and high tetragonality and density was essential to obtain high epsilon(r) of powders.