TiO2 is used in a variety of photochemical applications including catalysis, antibacterial coatings and dye-sensitized solar cells. The transformation of amorphous TiO2 into the three most common phases, anatase, rutile and brookite has been achieved under the appropriate experimental conditions. The amorphous TiO2 was obtained by adding titanium isopropoxide to isopropanol with a low concentration of water. A paste of amorphous titania was then mixed with different reactants and hydrothermally treated at elevated temperature in order to obtain a crystalline phase. Anatase nanoparticles were obtained by using acetic acid, while rutile nanoparticles were obtained using HCl. Titanates were formed with LiOH and KOH as reactants, while the use of NaOH results in brookite particles (>200 nm) after the formation of titanates as intermediate. The materials were characterized with X-ray diffraction and SEM.