The present invention relates to a non-colouring composition for treating keratin fibres comprising an aqueous dispersion of particles of hybrid hydrophobic acrylic film-forming polymer and a linear block silicone copolymer, and also to a method for treating keratin fibres using such a composition. The composition makes it possible to obtain a coating which is persistent towards shampooing operations, which leaves the treated fibres individualized, with an improved cosmetic feel and a provision of mass and volume.