The results of ab initio calculations of static electric properties of a series of cyclic conjugated ketones and thioketones are presented. Dipole moments, dipole polarizabilities, as well as the first and second hyperpolarizabilities, were evaluated at different levels of theory: SCF, CASSCF, MP2, CCSD, CCSD(T), and CASPT2 methods were used. Both MP2 and CASPT2 methods have been shown to perform well in the calculation of such properties. The dependence of the electric properties on the extent of the pi-electron conjugation and on the replacement of the keto by the thioketo group is analyzed. Cyclic conjugated thioketones are shown to exhibit significant nonlinear electric properties which make them prospective building blocks for nonlinear optical materials.