Nickel organophosphate/benzophenone U.V. stabilizers

A polyolefin resin composition comprising 1) a polyolefin resin and 2) a stabilizingly effective amount of a stabilizer consisting essentially of in synergistic combination A) a nickel salt of an organic ester of phosphoric acid having the following general formulae ##STR4## and B) a benzophenone selected from the group consisting of unsubstituted and substituted 2-hydroxybenzophenone and mixtures thereof and having the general formula ##STR5## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are the same or different and are alkyl, aryl, cycloalkyl, aralkyl or alkaryl radicals, X is hydroxyl or nothing and both or either R.sup.5 and R.sup.6 are nothing or the same or different straight or branched chain alkyl or alkoxy radical of 1 to 20 carbon atoms or either R.sup.5 and R.sup.6 but not both R.sup.5 and R.sup.6 are bromine, chlorine or fluorine.