The force fields employed in molecular dynamics (MD) simulations are determined under ambient conditions but not much attention is paid to their domain of applicability. Whether the current MD force fields have predictive power is an important issue that will affect the future developments in the field. Here, we determine the transport coefficients of ions in water from MD simulations at various temperatures and compare them with the available data. The results reveal that the rigid models used in standard MD force fields have difficulties in reproducing the observed temperature variations in conductivity data. (c) 2005 Elsevier B.V. All rights reserved.