The adsorption of sodium dodecylbenzenesulfonate (SDBS) on polystyrene particles was investigated. Monodisperse polystyrene particles were prepared by a one-step surfactant-free emulsion polymerization and their particle size varied from 0.4 to 3 mum. The surface charge density varies with particle size. Differences in the surface charge density have an effect on the adsorption behavior of surfactants at very high surface charge densities only. The areas per adsorbed SDBS molecule were determined by Maron’s soap titration method and were 50-60 angstrom2 at 22-degrees-C and 60-80 angstrom2 at 60-degrees-C for the latices depending on the surface charge density. The higher areas per adsorbed molecule at higher temperatures are explained by the larger thermal motion of the adsorbed molecules. The addition of long chain fatty alcohols (cosurfactants) such as dodecanol or cetyl alcohol influences the adsorption behavior of the surfactants. When the alcohols are added at low cosurfactant/surfactant ratios, there is only little influence, whereas at higher ratios the average area per adsorbed molecule of SDBS decreases sharply. This is explained by the fact that when adding alcohols there is a positive attraction between the tails of surfactant and alcohol, without simultaneously introducing additional repulsion through negatively charged groups. This positive effect is more pronounced at larger ratios of cosurfactant/surfactant than at lower ratios. At higher temperatures smaller average areas per adsorbed SDBS molecule are found.