The scattering from poly(ethylene oxide) adsorbed on polystyrene latex particles was measured as afunction of the isotopic composition of the aqueous solvent. Oscillations in the data were observed evenwhen the particle was matched in scattering length density to the solvent. These oscillations are a newand important characteristic of the scattering from an adsorbed polymer layer compared to the scatteringfrom free chains. The contrast variation approach allowed the scattering from the interference betweenthe layer and the particle to be measured explicitly. The data have been fitted using a model function tofind the volume fraction profile of the adsorbed layer without the complications that can arise from density-fluctuation contributions to the scattering. It was therefore possible to obtain the fluctuation contributionitself by simple subtraction. The fluctuation scattering was found to be in good agreement with scalingpredictions and with a new function derived for an exponential volume fraction profile.