Langmuir-Blodgett films containing a mixture of fullerene (C60) and arachidic acid (C20H40O2) were deposited on three different substrates (glass, quartz and silicon). The details of the dipping procedure are explained for three different values of the monolayer pressure. Optical studies in air at room temperature on films of various thicknesses deposited on quartz substrates were performed. From transmittivity and reflectivity measurements the refractive index n and extinction coefficient k have been evaluated in the UV-visible spectral range. Finally, a preliminary structural analysis carried out by means of scanning electron microscopy has shown that the films are homogeneous with some isolated cracks.