The cluster model approach within the B3LYP, density functional theory based, computational method has been used to investigate the coordination modes and adsorption sites involved in the interaction of CO2 on Pd(111). Three different surface species corresponding to two coordination modes only, η1-C and η2-side-on, are predicted. These are an almost undistorted CO2 molecule and two highly bent adsorbed species. The undistorted adsorbate appears at a rather large distance from the surface and is tentatively attributed to a precursor physisorbed state. The other two species closely resemble CO2- and, in both cases, the equilibrium distance above the surface is much smaller than in the previous case. These two species correspond to CO2 chemisorbed in the η1-C and η2-side-on coordination modes. The two chemisorbed species have very similar geometrical parameters and vibrational frequencies, and hence it is not possible to use these properties to differentiate both species. Nevertheless, the larger energetic stabilization of the η1-C chemisorbed CO2 suggests that this is the one which is observed experimentally.