In comparison with other commercial light stabilizers, sterically hindered 4-hydroxybenzoates are found to possess only a weak power, if they are used for low density polyethylene (LDPE). It is known that these benzoates exhibit significant synergistic effects together with 2-hydroxybenzophenones and hindered amine light stabilizers in light stabilization of high-density and linear low-density polyethylene. The light stabilizing efficiencies of the above mentioned stabilizers and mixtures of them in different weight ratios are determined by weathering in a Xenotest 150 unit. Only small synergistic effects of about 15 −30% are found for light stabilizing LDPE. The effects can be explained by the stabilizing efficiency of sterically hindered 4-hydroxybenzoates during processing. Combining of light stabilizing structure components like 2-hydroxy-benzophenone resp. 2, 2, 6, 6-tetramethylpiperidine with sterically hindered 4-hydroxybenzoates in one stabilizer molecule only, from the first mentioned combination, results a powerful light stabilizer. Its efficiency is the sum of the powers of the single structure components.