Non-equilibrium molecular dynamics (NEMD) simulations were carried out to study the ionic conductivities of 8% yttria-stabilized zirconia (YSZ) at 900, 1273 and 1759 K. The conductivities estimated from NEMD simulations were compared with those calculated from diffusivities obtained in equilibrium molecular dynamics simulation according to the Nernst-Einstein relation. The agreement with equilibrium molecular dynamics results is better at low temperature whereas the agreement with experimental data is better at high temperature. (C) 2004 Elsevier B.V. All rights reserved.