The present paper is concerned with computation of the radiation-natural convection interactions in an inclined "T" form cavity. The cavity contains two symmetrically identical isothermal blocks and is vented by two opening located in a vertical median axis at the top and the bottom parts of the cavity. Calculations are made by using a finite volume method and an efficient numerical procedure is introduced for calculating the view factors, with shadow effects included. Effects of Rayleigh number Ra and inclination angle phi are investigated for Pr = 0.71 in presence and in absence of the radiation exchange. Results are reported in terms of isotherms, streamlines, local and average Nusselt numbers and mass flow rate. In light of the obtained results, we can conclude that the heat transfer decreases with increasing phi. In addition, the increase of Ra and the taking into account of the radiation exchange produce a considerable increase in the heat transfer. (C) 2010 Elsevier Ltd. All rights reserved.