Transient solutions were obtained for heat transfer through a semitransparent porous medium placed in a flow passage and submitted to incident radiation. The one-dimensional physical model takes into account, conduction, convection and radiation simultaneously. The porous medium is assumed to be homogenous continuum, which absorbs, emits and scatters thermal radiation. A fully implicit time-marching algorithm was used to solve the nonlinear coupled energy equations for gas and porous medium numerically. The present study utilizes the differential-discrete-ordinate (DDO) method to account for the radiation contribution. The effects of the Reynolds number, optical depth, anisotropic scattering, conduction-radiation parameter and scattering albedo on temperatures and fluxes profiles are investigated. (C) 2002 Published by Elsevier Science Ltd.