The problem of steady natural convection in an inclined porous cavity with a discrete heat source on a wall is studied numerically. Non-Darcy and thermal dispersion effects are taken into consideration in the momentum and energy equations, respectively. Wall effects on porosity, permeability and thermal dispersion are also taken into account. The governing equations in terms of vorticity, stream function and temperature are solved numerically by a finite difference method. It is found that a secondary vortex begins to appear in the cavity at a location above the discrete heat source if the media Rayleigh number is sufficiently high; the intensity of the vortex increases with the eccentricity of the heat source and the inclination angle of the cavity. For a porous cavity at zero inclination angle with a vertical wall at a uniform temperature, the predicted average Nusselt numbers based on the present model are found to be in better agreement with experimental data; the similarity solution (based on the boundary approximation, Darcy law with no thermal dispersion in an infinite constant porosity medium) is found to be accurate for the media Rayleigh number greater than 30.