The invention relates to powder compositions hardenable by radiation usable for preparing paints and varnishes. These powder compositions contain an ethylenically unsaturated resin, a phosphorous containing compound and, eventually, a monomer or oligomer The powder compositions of the invention are especially suited for coating over metal and combine upon melting at low temperatures and curing by radiation a series of properties such as good flow and film flexibility along with an outstanding adhesion to the substrate.