In this work, the effects of surface radiation and number of partitions on the heat transfer and flow structures in a rectangular enclosure, inclined by phi = 45 degrees with respect to the horizontal plane, have been studied numerically. The two vertical walls of the enclosure, of an aspect ratio equal to 4, are heated with uniform different temperatures, while the others are adiabatic. The equations controlling the system are solved by a finite volume method. The SIMPLER algorithm was used for the velocity-pressure coupling, and the view factors were integrated by a Monte Carlo method. It was found that the total heat transfer in the enclosure is increased under thermal radiation heat flux and reduced significantly with increasing the number of partitions. (C) 2007 Elsevier Ltd. All rights reserved.