Results obtained in a batch adsorption system with constant volume showed that preadsorption of small amounts of propane on NaA zeolite can significantly slow down the rate of carbon dioxide uptake. The observed decrease in the carbon dioxide uptake rate was related to a decrease in accessibility of the external surface of the microcrystallites due to the effect of an external film resistance created by the preadsorbed propane molecules. Small amounts of preadsorbed propane localized inside the zeolite microcrystallites were found to have no affect on the COP adsorption rate. Experiments carried out using the frequency response technique confirmed the significant influence of the external film resistance on the kinetics of adsorption of carbon dioxide/propane mixtures on 4A zeolite even at low propane concentrations (2-3%).