The present work demonstrates a parametric study for a conjugate natural convection cooled substrate mounted heat sources placed inside an enclosure. This particular situation has direct relevance in electronic cooling applications. The governing coupled non-dimensional transport equations were solved using the finite volume technique. It is found that Ra. Pr and enclosure boundary condition affects strongly the fluid flow and heat transfer characteristics. It is concluded that non-dimensional temperature is maximum for Pr = 150. Numerical correlation for maximum protrusion temperature and Nusselt number were presented for wide range of Pr, Ra and enclosure boundary conditions. (C) 2000 Published by Elsevier Science S.A. All rights reserved.The present work demonstrates a parametric study for a conjugate natural convection cooled substrate mounted heat sources placed inside an enclosure. This particular situation has direct relevance in electronic cooling applications. The governing coupled non-dimensional transport equations were solved using the finite volume technique. It is found that Ra,Pr and enclosure boundary condition affects strongly the fluid flow and heat transfer characteristics. It is concluded that non-dimensional temperature is maximum for Pr = 150. Numerical correlation for maximum protrusion temperature and Nusselt number were presented for wide range of Pr,Ra and enclosure boundary conditions.