Biosorption of ochratoxin A (OA) onto yeast biomass appears to be a reasonably low cost decontamination method. In vitro adsorption of OA onto three yeast industry by-products: a vinasse containing yeast cell walls (EX 16), a purified yeast beta-glucan (BETA) and a yeast cell wall fraction (LEC) was examined at 25 degrees C. Seven classical adsorption models were tested to provide the best description of toxin adsorption. A comparison of these models was performed using the magnitude of the coefficient of determination R-2 for the linear models and the value of the sum of normalised errors (SNE) for linear and non-linear models. Based on the R-2 and the SNE values, Hill, Freundlich and Brunauer-Emmett-Teller equations produced the best models for OA biosorption onto respectively, EX16, BETA and LEC. For these best models, the values of isotherm constants were consistent when measured using both linear and non-linear calculations. The SNE calculation procedure presented in this paper in association with the linear equation analysis method is an appropriate approach for designing a better adsorption isothermal model. (c) 2006 Elsevier Ltd. All rights reserved.