Technical Abstract: Cellulose nanoreinforcements have been used to improve mechanical and barrier properties of biopolymers, whose performance is usually poor when compared to those of synthetic polymers. Nanocomposite edible films have been developed by adding cellulose nanofibers (CNF) in different concentrations (up to 36 g/100 g) as nanoreinforcement to mango puree-based edible films. The effect of CNF was studied in terms of tensile properties, water vapor permeability, and glass transition temperature (Tg) of the nanocomposite films. CNF were effective in increasing tensile strength, and its effect on Young’s modulus was even more noticeable, especially at higher concentrations, suggesting the formation of a fibrillar network within them matrix. The addition of CNF was also effective to improve water vapor barrier of the films. Its influence on Tg was small but significant. The study demonstrated that the properties of mango puree edible films can be significantly improved through CNF reinforcement.