The present investigation shows the advances in the synthesisSynthesis of BaTiO3BaTiO3 (BT) by the hydrothermal method. Two experiments were carried out; in the first one, the reactor was cooled in a controlled way until reaching room temperatureTemperature, and in the second experiment, the reactor, after 24 h of synthesisSynthesis inside the furnace, was cooled suddenly. As a result, variations were observed in the particle sizesParticle size of both experiments, obtaining the smallest size, 267 nm, by cooling the powders, while the powders cooled in a controlled manner, the size increased, 452 nm, and presented 2 groups of size distribution. XRDX-Ray Diffraction (XRD) analysis showed no evidence of secondary phase formation, only the desired BT phase; on the other hand, SEMScanning Electron Microscopy (SEM) images allow us to distinguish the morphologies depending on the cooling rate. Raman spectroscopyRaman spectroscopy studies reveal the stability of the tetragonal phase after sinteringSintering.