Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The adsorption and desorption isotherms of tapioca flour was performed in the range of water activity (aw) from 0.22 to 0.92 at 25 degrees C, and the applicability of six mathematical models in data prediction was evaluated. The tapioca flour presented Type II isotherm (sigmoid), and the hysteresis effect was not observed. For the microbiological stability, the moisture of tapioca flour should not exceed 10.1%. The monolayer moisture content value indicates that the drying process of tapioca flour should not be conducted to obtain moisture levels lower than 4.92% to avoid unnecessary power consumption. The data fit showed that all mathematical models are able to predict the adsorption isotherm of tapioca flour, and the models of Handerson, Smith, GAB and BET are able to predict the desorption isotherm.474870874Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)