Cellulose acetate phthalate nanodispersions were prepared in the form of a redispersible powder by a new preparation technique based on the salting-out process between two miscible solvents. This method involved the selection of salts producing the salting-out of acetone from water. Poly(vinyl alcohol) was used as protective colloid during the particle formation step and in the finished product. For a pharmaceutical use, the advantage of this new technique is that the process does not require any surfactant or increase in temperature and thus may be useful for biopolymers or heat-sensitive substances. These nanodispersions may also be dried by lyophilization and the particles subsequently redispersed in an aqueous medium before use.