The dependence of surface enhanced Raman scattering intensity on the concentration of polystyrene solution was investigated. The spectral quality and the Raman line intensities of the enhanced scattering of polystyrene deposited on silver foil, roughened with nitric acid, were related to the concentration. The band intensity versus concentration plot displays a turning point corresponding to the critical concentration for coil shrinkage. The observed phenomena are in accordance with Qian’s proposal for the existence of a critical concentration for coil shrinkage, based on excimer fluorescence studies of polymer solutions.