Neutron and X-ray reflectivity measurements of a thin film of cermet (ceramic-metal) made by co-sputtering Pt and Al2O3 on the surface of a flat piece of float glass are presented. From the analysis of the specular and off-specular measurements, the morphology of the Pt clusters which are embedded in the Al2O3 matrix is determined by adjusting a model to the observed data. It is found that the structure of such films presents a certain degree of order in the direction normal to the surface of the films but no correlation (or with a very short correlation length not measurable by this technique) in the plane of the film.