UV-Photoprotective oil-in-water emulsions well suited for photoprotecting the skin, lips and/or hair against the damaging effects of UV-radiation, the oil globules of which having an average size of at most 500 nm and containing particles of at least one ionic polymer and at least one UV-radiation-screening system, such screening system comprising at least one 4,4-diarylbutadiene UV-A-screening agent.