Fine particulate and phase pure barium titanate with its average particle size as small as 120 nm and its tetragonality as high as 1.0085 was obtained by adding bovine serum albumin (BSA) to the reactant mixture comprising fine particulate BaCO3 and TiO2. In the presence of BSA, BaCO3 decomposed at substantially lower temperatures as a consequence of coordination of BSA preferentially to the ligand field of Ba. Elimination of remaining free carbon by increasing oxygen partial pressure under flowing air was one of the technical key issues of the high crystallinity and sinterability of the product.