Copper and manganese additives for pressureless sintering of Ce-TZP have been studied, the former because its atomic radius is close to that of Ce4+, the latter because its atomic radius is close to that of Zr4+. The temperature at which shrinkage begins did not decrease when using CuO or MnO2, but at a given temperature, the sintering rate was higher. CuO and MnO2 were also very effective in improving both the tetragonal phase content retained at room temperature and the mechanical properties (hardness, bending strength and toughness).