The classical Graetz methodology is applied to investigate the thermal development of forced convection in a parallel plate channel filled by a saturated porous medium, with walls held at constant temperature, for the case of a non-Newtonian fluid of power-law type. A Brinkman-Forchheimer model is used for the momentum equation. The analysis for the case of small modified Darcy number leads to expressions for the local Nusselt number and average Nusselt number as functions of the dimensionless longitudinal coordinate, the power-law index, a modified Darcy number, and a modified Reynolds-Forchheimer number (with the last three parameters being involved via a boundary-layer thickness). (C) 2004 Elsevier Ltd. All rights reserved.