A simple mathematical model to predict the oxygen permeability coefficient of multilayer films is presented in this work. Four multilayer systems and the corresponding monolayer films were tested: OPP/OPP (oriented polypropylene), PPcoex/PPcast (co-extruded and casted polypropylene, respectively), PET/PPcast (polyethylenterephthalate and casted polypropylene, respectively) and OPA/OPA/PE (oriented polyamide and polyethylene, respectively). To validate the model, oxygen permeability tests were conducted at 23 degrees C. In particular, the oxygen permeability coefficients of the monolayer films were firstly measured and then used to predict that of the multilayer film. This value was compared with that measured and the percentage error calculated. In the case of the PET/PPcast and OPA/OPA/PE systems, the oxygen barrier properties were measured and predicted at water activity ranging from 0% to 90%. Results showed that the percentage error between the experimental data and the predicted values by the model was close or below to 10% in most of the cases. (C) 2010 Elsevier Ltd. All rights reserved.