Synthesis of A-site deficient perovskite-type compound La2/3TiO3−δ was carried out using a hydrothermal treatment and a combination of sol–gel method, followed by combustion and heat treatment. The structure, morphology and particle size of the synthesized compounds were characterized by X-ray diffractionand scanning electron microscopy. It was shown that the perovskite particles obtained by both hydrothermal treatment and sol–gel technique have a cubic crystal lattice, and crystallite sizes are 31 and 23nm, respectively. According to SEM results, a hydrothermal synthesis led to the formation of elliptical nanoparticles with a size of 40nm in length. In the case of sol–gel technique, irregularly shaped agglomerates with 60nm size were observed.The study of the behavior of the A-site deficient perovskite-type compound La2/3TiO3−δ during heating was carried out with the help of complex thermal analysis. The dielectric spectroscopy method was used to obtain temperature and frequency dependences of dielectric constant and dielectric loss tangent for synthesized samples of La2/3TiO3−δ.