Cosmetic composition comprising a polymer blend The invention relates to a composition comprising, in a physiologically acceptable medium, at least a first polymer with a weight-average molecular mass of less than 100 000, comprising a) a polymer skeleton containing hydrocarbon-based repeating Units containing at least one hetero atom, and optionally b) at least one pendent fatty chain and/or at least one terminal fatty chain, which may be functionalized, containing from 6 to 120 carbon atoms and being linked to these hydrocarbon-based units, a dispersion of particles of a second film-forming polymer that is insoluble in said medium. Application to make-up and caring for keratin materials.