We have prepared Co/Pt multilayers by evaporation in UHV on MgO (100) substrates kept at various temperatures. Most of the samples were grown on a Pt buffer layer. Magnetic and magneto-optical properties have been studied. The surface anisotropy Ks for MgO substrates is 0.35 erg.cm−2 which is smaller than 0.6 erg.cm−2 obtained for glass substrates. The effect of the growth conditions on Ks is observed only for t(Co)<10 Å where the crossover to Keff>O occurs. Deposition at higher temperature leads to an increase in the coercivity. The magnetization and the anisotropy is practically temperature independent in the range 5 to 295 K. However the coercivity increases sharply below 100K.