The present work investigates the efficiency of the Multigrid method when applied to solve laminar steady mixed convection flow in a vented enclosure with an isothermal vertical wall and filled with a fluid-saturated porous medium is investigated numerically. The numerical method includes finite volume discretization with upwind scheme on structure orthogonal regular meshes. Performance of the correction storage (CS) Multigrid algorithm is compared for different numbers of sweeps in each grid level. Up to four grids, for both Multigrid V- and W- cycles, are presented.