Pressurised cosmetic compositions provided in pressurised form in an aerosol device in the presence of a propellant, and capable of forming a foam, are disclosed. Said compositions comprise a cosmetically acceptable medium containing at least one binding polymer, at least one oxyalkylene silicone and at least 30 wt % of a water-soluble solvent having a boiling point lower than 85.degree. C. Foams produced by the expansion in air of said cosmetic compositions are also disclosed. Furthermore, a method for cosmetically treating keratin fibres such as hair, wherein a foam produced by the expansion in air of said cosmetic composition is applied to said keratin fibres, is disclosed.