The present invention thus relates to a solid composition, in particular in the form of a loose or compact powder, comprising, in a cosmetically acceptable medium: a) at least one pulverulent phase b) at least one lipophilic organic UV screening agent characterized in that the pulverulent phase comprises at least aerogel particles of hydrophobic silica exhibiting a specific surface per unit of weight (SW) ranging from 200 to 1500 m2/g, preferably from 600 to 1200 m2/g and better still from 600 to 800 m2/g, and a size, expressed as volume-average diameter (D[0.5]), of less than 1500 μm and preferably ranging from 1 to 30 μm, more preferably from 5 to 25 μm, better still from 5 to 20 μm and even better still from 5 to 15 μm. It also relates to a cosmetic method for caring for and/or making up human keratinous substances, in particular the skin of the body or of the face or the hair, comprising at least the application, to the surface of the keratinous substance, of at least one composition as defined above.