In this paper a heat transfer model is presented for the determination of the temperature field of a circuit board with electronic components placed upon it and undergoing the process of surface mounting. The model is solved for a simple board configuration and the effect of the major parameters of the problem on the temperature field of the board and the components is obtained. Regions of sharp thermal gradients (causing thermal stresses and possible cracking) are identified. These regions are usually located around the edges of the electronic components as well as underneath the edges of these components within the board material.