In this paper, an optimization study involving five variable parameters which are critical in evaluating the thermal performance of the air jet flow impingement over porous heat sinks in mixed convection regime is presented. The variable parameters include porous block height, channel height, jet width, porosity and Darcy number. The Lattice Boltzmann method for porous media is used as the numerical tool to simulate the objective functions in terms of Nusselt number and pressure drop. Kriging method combined with Genetic algorithm is used to generate the optimal Pareto plot. Three optimal cases from the pareto plot showing maximum, minimum and optimum Nusselt numbers and pressure drop are considered. The optimized results show that the porosity and Darcy number are relatively invariant along the pareto surface. Thus the geometry of the channel and porous block are the most significant parameters governing Nusselt number and pressure drop values. The results from optimization corresponding to the three optimal cases are analyzed in detail. The local variation in Nusselt number for these cases is also plotted to understand the effect of the channel and porous heat sink parameters on heat transfer.