We have measured,for the first time,the low frequency (unclamped)electro-optic and piezoelectric coefficients in Ce:BaTiO3 crystals using interferometric techniques.When the piezoelectric contribution to the phase change by a beam passing through the crystals is ruled out,the unclamped electro-optic coefficients of the poled Ce:BaTiO3 single crystals are r42=1945±220pm/V and r13=11.8±1pm/V.Consequently,accurate values of the Pockels coefficients are provided for researching the photorefractive effect and theoretical study of the Ce:BaTiO3 crystal.