Topically applicable high SPF cosmetic/dermatological UV-screening compositions suited for the photoprotection of the skin and/or hair, comprise (a) particulates of at least one insoluble organic UV-screening agent having a particle size ranging from 10 nm to 5 .mu.m, as a first screening agent, and (b) at least one 4,4-diarylbutadiene compound, as a second screening agent, formulated into a topically applicable, cosmetically/dermatologically acceptable vehicle therefor.