Low temperature heat capacity of powder (0.45 mu m) and sintered samples of yttria-doped zirconia (ZrO2)(1-x)(Y2O3)(x) (x = 0.0776, 0.0970) was measured by adiabatic calorimetry between 13 and 300 K. The powder samples showed excess heat capacity over that of sintered samples, which was ascribed to adsorbates on the surface of the powder samples. Excess heat capacity due to low-lying mode was observed in the doped samples compared with non-doped zirconia (x = 0), which was discussed from the viewpoint of oxygen vacancies in the crystals.