Convective-radiative heat transfer in an enclosure having finite thickness heat-conducting walls at local heating at the bottom of the cavity has been numerically studied. Heat exchange with an environment due to convection and radiation has been considered on one of external sides of the decision region. The effect of parameters such as the Grashof number, the transient factor, the optical thickness and the solid wall thermal conductivity both on the local thermo-hydrodynamic characteristics such as streamlines and temperature fields and on the integral parameter like the average Nusselt number on the heat source surface has been analysed. (C) 2008 Elsevier Ltd. All rights reserved.