Optical fixed-angle reflectometry was examined as a technique to study the adsorption of organics (polymers, surfactants) on metallic substrates. Calculations were made to evaluate the sensitivity of the method with regard to the refractive index and the thickness of the metal and the incidence angle. Theoretical results show that Ti, Cr, V, Zr, and gold have an appropriate sensitivity for detecting the adsorption accurately. Parallel experiments using gold and silica substrates and polyvinylimidazole (PVI) as an organic material were carried out. Adsorption measurements as a function of polymer concentration, pH, and ionic strength were in accordance with expected trends.