The invention relates to a method of increasing the storage stability and preventing yellowing under the action of UV-light, of a UV-curable composition comprising a1) at least one oligomer, co-oligomer, polymer or copolymer or a mixture thereof having at least one ethylenically unsaturated bond; or a2) a mixture of at least one ethylenically unsaturated monomer with at least one oligomer, co-oligomer, polymer or copolymer having at least one ethylenically unsaturated bond; and one or more .alpha.-hydroxycycloalkylphenyl ketone or bisacylphosphine oxide photoinitiators, which method comprises adding b) at least one stable sterically hindered nitroxyl free-radical or at least one compound of the benzofuran-2-one type or a mixture of the two compounds.