Adsorption kinetics of a polydisperse sample of poly(ethylene oxide) were studied using total internal reflectance fluorescence (TIRF), a method whose signal is approximately proportional to the adsorbed chain number. The initial stages of the adsorption process were found to be approximately transport-limited, dominated by single-chain adsorption for free solution concentrations below 100 ppm and clusters at higher concentrations. In the intermediate stages of single-chain adsorption, an overshoot occurs. The timing of the overshoot is extremely sensitive to the molecular weight distribution of the sample, and various populations of different molecular weights within the sample can be resolved. The signal decrease after the overshoot is attributed to one or both of the following processes : replacement of initially adsorbed short chains with ones of higher molecular weight, or interfacial reconfigurations driven by the filling of the surface and affecting the quantum yield of the fluorescent tag on the chain end.