Permeability measurements were performed on several polymeric films used for packaging applications. The results were analysed in terms of the ratio of the permeabilities between two gases. Moreover, recent experimental results and data reported in the literature have been compared with a simple relationship reported by van Krevelen for predicting the transport properties of high molecular weight polymers. Finally, a suggestion is made for improving the accuracy of the prediction of the permeabilities for high molecular weight polymers.