The local coordination structure around Yttrium ions in yttria stabilized zirconia (YSZ) has been investigated by Y-89 MAS-NMR. The NMR spectrum showed multiple peaks corresponding to yttrium ions in different coordination numbers. The compositional dependence of spectra was observed. Yttrium ions of different oxygen coordination number were quantified. The oxygen vacancy concentration around the cations was determined. It was found that the vacancies were distributed around Zirconium ions in lower Y2O3 concentrations, and the vacancy concentration located to Yttrium began increasing at concentrations above 10 mol% Y2O3. The local structure change was able to be directly observed by 89Y NMR measurements. (c) 2006 Elsevier B.V. All rights reserved.