The heat and mass transfer characteristics of natural convection about a vertical surface embedded in a saturated porous medium subjected to a magnetic field is numerically studied, by taking into account the diffusion-thermo (Dufour) and thermal-diffusion (Soret) effects. The governing partial differential equations are transformed into a set of coupled differential equations, which are solved numerically using a finite difference method. Dimensionless velocity, temperature and concentration profiles are presented graphically for various values of the magnetic number M and Lewis number Le, and for fixed values of the Dufour number D-f, Soret number S-r and buoyancy number N. Three cases are considered and presented in tables, for the local Nusselt number and local Sherwood number corresponding to Le = 1 and various values of M, N, D-f and S-r. Increasing the value of M increases the local Nusselt number and local Sherwood number. (C) 2003 Elsevier Ltd. All rights reserved.