The aim of this work was to evaluate the feasibility of using power ultrasound to improve the atmospheric freeze-drying of mushroom, as interesting alternative to vacuum freezedrying, considering not only kinetic effects but also the final quality. For that purpose, mushroom slices (Agaricus bisporus) were dried (-10 ºC and 2 m/s) with (24.6 and 12.3 kW/m 3 ; 21.9 kHz) and without ultrasound application. The application of ultrasound significantly influenced the drying kinetics, increasing the effective diffusivity up to 280 % and shortening drying time up to 74 %. As for the quality parameters (color, texture, rehydration and cell damage), no remarkable influence of the ultrasound application was observed. Therefore, the application of power ultrasound during the atmospheric freezedrying of mushroom might be considered as an interesting technology providing that it significantly increased the process kinetics without greatly affecting the quality of the final product