Summary A mathematical model was developed from experimental measurements to describe the evolution of the O 2 , CO 2 and ethylene in a modified atmosphere packaging system for Cavendish bananas. The respiration and ethylene production in the fruits were experimentally obtained from a closed system method and then represented by Michaelis–Menten equations of enzyme kinetics. The gas transfer through the packaging was described by a Fick's diffusion equation, and the temperature dependence was represented based on the Arrhenius law. The model was validated by packaging the fruit in perforated bags of polypropylene and low density polyethylene at 12 °C for a period of 8 days. With the developed model it was possible to satisfactorily describe the experimental evolution of the gas content in the headspace of the packages, obtaining coefficients of determination ( R 2 ) of 0.93 for the O 2 levels, 0.90–0.91 for the CO 2 levels, and 0.89–0.93 for the ethylene levels.