Strontium titanate and barium titanate ceramics prepared by a reaction-sintering process were investigated. The mixture of raw materials of stoichiometric SrTiO3 and BaTiO3 was pressed and sintered into ceramics without any calcination stage involved. A density 4.99 g/cm(3) (97.5% of the theoretic value) was found in SrTiO3 after 6 h sintering at 1,370 degrees C. Grains less than 1.5 mu m were formed at 1,300-1,330 degrees C and became 2.2-3.3 mu m at 1,350-1,370 degrees C SrTiO3. A density 5.89 g/cm(3) (97.9% of the theoretic value) was found in BaTiO3 after 6 h sintering at 1,400 degrees C. Merged grains were observed in BaTiO3 and were less than 10 mu m after sintered at 1,400 degrees C.