Adsorption of fluorescein isothiocyanate labeled polystyrene at the toluene−water interface is studied using two-photon fluorescence microscopy. We have developed a protocol to estimate the amount of polymer adsorbed at the interface. The measured surface excess is strongly influenced by fluorescence resonance energy transfer between neighboring fluorescein units. After accounting for this effect, we are able to estimate the surface excess to be approximately 1 mg/m2, which indicates a brushlike conformation for the adsorbed molecules.