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 23 nm, respectively. According to SEM results, a hydrothermal synthesis led to the formation of elliptical nanoparticles with a size of 40 nm in length. In the case of sol–gel technique, irregularly shaped agglomerates with 60 nm 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