In the present study, BaTiO 3 nanospheres with a uniform particle size of around 100 nm were prepared by a hydrothermal route using Ba(OH) 2 .8H 2 O and TiO 2 nanoparticles. Experimental results revealed that the main influencing factors for the formation of BaTiO 3 nanospheres were molar Ba/Ti ratio ( R Ba/Ti ), hydrothermal temperature, and time. Highly-dispersed BaTiO 3 nanospheres (100 nm) were obtained under the optimum hydrothermal conditions at temperature = 200°C, time = 12 h, and R Ba/Ti = 1.5. Under these optimum conditions, BaTiO 3 ceramics were synthesized from the as-prepared BaTiO 3 nanospheres, and their structural, microstructural, and electrical properties were investigated. The BaTiO 3 ceramics exhibited a high dielectric constant of 7300 at a Curie temperature of 125 °C, great density (ρ), 5.83 g cm –3 ; large dielectric constant at room temperature e r = 3586 and tan d = 0.03, high remanant polarization P r = 10.6 μC cm –2 , low coercive field E c = 4.5 kVcm –1 .