In this study, highly crystalline BaTiO 3 and SrTiO 3 nanoparticles were synthesized by bi-modal distribution solution process followed by annealing at different temperatures. The impact of annealing temperatures on the nanoparticles was investigated by their various chemical, structural and surface properties. The particle sizes of both BaTiO 3 and SrTiO 3 increased from 30-80 nm with increase in annealing temperature due to the agglomeration of the nanoparticles. It was found that the optical band gap of BaTiO 3 and SrTiO 3 was considerably decreased with the increase of annealing temperatures from 500 -900°C. With the observed results, we can say that annealing BaTiO 3 and SrTiO 3 nanoparticles significantly enhance their optical, structural, morphological and crystalline properties.