The present investigation is concerned with the development of a new iterative method permitting, for a Fickian sorption of a binary liquid mixture in thin polymer sheets, the simultaneous determination of the self-diffusion coefficients of the components of the mixture, and their uptake fractions at equilibrium. The approach is based on a new equation describing a parallel Fickian sorption of the components of the mixture into thin polymer sheets. The procedure was tested with ideal and Monte Carlo simulated data. The method, applied to ideal simulated data that corresponded to various values of D-1, D-2 and f, perfectly extracted the desired parameters. The application of the method to Monte Carlo simulated data revealed that this method is fairly applicable even when the simulated data are considerably obscured by "noise". Finally, the proposed method was successfully applied to the experimental data concerning the sorption kinetics of ethanol-water mixture (75 vol % in EtOH) at 37 degrees C in thin polymeric sheets of triethyleneglycol dimethacrylate (TEGDMA). (C) 2007 Wiley Periodicals, Inc.