In this study, a method is proposed for determining the chloride diffusion coefficient in mortar from accelerated chloride migration test. The effective chloride diffusion coefficient is calculated on the basis of the Nernst-Planck equation. A good correlation is observed between the effective diffusion coefficient measured from the chloride ion concentration in the anode cell and that in the cathode cell. In order to avoid sampling and analyzing chlorides during the migration test, the linear portion of the charge passed is used to assess the steady state period, and the slope of the linear portion of the Q-time curve is used to determine the effective chloride diffusion coefficients in the anode and cathode cells. (C) 2003 Elsevier Science Ltd. All rights reserved.