The prediction by Cahn (1977,J. chem. Phys.,66,3677) that a two phase fluid at a wall shows a wetting transition accompanied by a thick-thin film (prewetting) transition as the temperature increases towards the critical value where the fluid becomes uniform has been supported by a number of workers using free energy density functional theory. Due to the use of strong and varying approximations the support is of a qualitative nature and, in the absence of simulation verification of wetting-prewetting in simple solid-fluid systems, the quantitative aspects of the phenomenon are controversial. In this work we apply the GvdW functionals, previously successfully applied to both adsorption and gas/liquid interfaces in simple fluids to the wetting problem. The system consists of a carbon dioxide wall represented as a uniform continuum and an argon fluid interacting within itself and with the wall by appropriate Lennard-Jones (12–6) potentials. We focus our attention on the role of non-local entropy (responsible for hard-sphere oscillatory liquid structures) in the wetting phenomenon. The results of both semianalytical analysis based on the use of step-function fluid profiles and numerical optimization techniques yielding realistic profiles indicate that non-local entropy and the corresponding oscillatory structures play an important role in wetting by dropping the wetting temperature and stretching the prewetting line at which the thick-thin film transition occurs.