Langmuir films are 2D ordered arrays of amphiphilic molecules that form at an air water interface and can be transferred to a variety of surfaces to give Langmuir-Blodgett (LB) films. LB films are promising materials for building organized structures for molecular electronics and integrated optics. Many non-centrosymmetric LB films, including polymer films, show nonlinear properties (SHG, parametric amplification, electrooptic effect). For use as non- linear materials, LB films usually need to be more than 100 bilayers thick, i.e. > ca 0.4 micrometers . We have investigated the attenuation of light in such films. As the films become thicker surface and bulk inhomogeneities may cause an increase in the attenuation. We have investigated polymeric films samples of various thicknesses, both prepared by LB method and by spin coating, by SEM, Talystep, ellipsometry and we make some theoretical estimation about the influence of these factors on the attenuation of the films.