A theoretical model for the rate of entropy generation has been developed for an axi-symmetric laminar diffusion flame in which a cylindrical fuel stream is surrounded by a co-flowing oxidizer jet in a confined environment. The solution for the diffusion name is generated by solving the mass, momentum, energy and species conservation equations, simultaneously, using a finite difference method with the appropriate boundary conditions. A single step global reaction kinetics between fuel and oxygen is considered for the solution. The effects of varying the inlet air temperature and the air-fuel ratio on the total rate of entropy generation as well as the contribution of the individual subprocesses towards entropy generation are investigated.