Modified atmosphere packaging (MAP) relies on the interplay between the product respiration and the package film permeability with the aim of maintaining initial quality and extending shelf-life of fresh produce. The aim of this work was to evaluate the effect of MAP design parameters (number of perforations, weight of CO2 scavenger and amount of product) on quality of sliced button mushrooms. Sliced mushrooms were packed in a tray, covered with biobased film, and were stored at 10 ºC for 3 days. Headspace gas composition and quality parameters of sliced mushrooms (weight loss, pH, firmness and colour) were measured throughout the storage period. All factors produced a significant effect (p< 0.05) on weight loss of mushrooms and the presence of CO2 scavenger increased weight loss. Addition of CO2 scavenger in the package increased the deterioration of mushrooms, showing that a properly design MAP would be better for packing sliced mushrooms. Good MAP design requires consideration of weight of mushrooms to be packed and number of perforations in the film in order to achieve the best headspace gas composition for prolonging the shelf life of fresh sliced mushrooms. The optimal conditions found were 110 g of sliced mushrooms and 2 perforations (0.33 mm diameter) which led to an equilibrium gas composition of 3.6 % O2 and 11.5 % CO2 after 3 days of storage at 10 ºC.