In this paper is investigated electrical properties the perovskite[1]like oxide CaCu3Ti4O12 (CCTO) such as CaCuTiM O, where M = V (x = 0,1-0,5) and Zr (x = 0,3), possessing 34-xx 12 large effective dielectric permittivity and the temperature independence of the dielectric constant in wide frequency range. The aim of this paper is to attempt to establish the cause of the occurrence of high values of the dielectric constant.