Combined effects of Soret (thermal-diffusion) and Dufour (diffusion-thermo) on mixed convection over a stretching sheet embedded in a saturated porous medium in the presence of thermal radiation and first-order chemical reaction are studied. The effects of various physical parameters on the dimensionless velocity, temperature and concentration profiles are presented graphically. In addition, numerical results for the local skin friction coefficient, the local Nusselt number, and the local Sherwood number are discussed. It is found that temperature profiles increase with increase in the thermal radiation parameter and Dufour number. The effect of Soret number is to increase the concentration distribution whereas reverse effect is seen by increasing the values of the chemical reaction rate parameter on concentration distribution. (C) 2012 Elsevier Ltd. All rights reserved.