Radiation heat transfer between rectangular electronic components on a printed circuit board and the walls of its enclosure is studied analytically using a Monte Carlo method. The radiation heat transfer between the electronic components and the cover is determined for the cases of diffuse and specular surfaces with constant properties, and for diffuse and specular surfaces with variable temperature and direction-dependent properties. The radiation interchange between the components and the cover of the enclosure are determined and presented for various dimensionless parameters and surface emissivities in tabular and graphical forms. The radiation heat transfer, in general, is found to be comparable in magnitude to natural-convection heat transfer at operating conditions encountered in practice. It is shown that radiation can serve as an effective heat transfer mechanism for the cooling of electronic components in sealed enclosures cooled externally.