Both oriented and non-oriented ferroxplana $Co_{1-x}Zn_xZ(Ba_3Co_{2(1-x)}Zn_{2x} Fe_{24}O_{41})$ with x=0.00, 0.45 were prepared by conventional ceramic method. The magnetostrictions of thus prepared specimens were measured by use of the three terminal capacitor device at room temperature. The magnitude of measured values was approximately five times greater than that of ZnY ferroxplana. The easy-magnetization plane at room temperature of both CoZ and Co0.55 $Zn_{0.45}$Z was their basal plane. The magentostrictions in the basal plane and the other planes showed saturated values at magnetic field intensity of about 2Koe and 4Koe, respectively. The magnetostriction constants $K_1, ; K_2, ;K_3; and; K_4$ for CoZ were -2.4, -10.5, -5.9 and -45.2$ imes10^{-6}$ , while those for $Co_{0.55}Zn_{0.45}Z$ were +0.1, -1.2, -6.3 and -39.0$ imes$10^{-6}</TEX>, , respectively.