The accelerated UV photodegradation process of low-density polyethylene films, formulated with two photostabilizers and two antioxidants, was studied to evaluate the effect of different combinations of UV stabilizers and antioxidants on the overall photodegradation process. An experimental design, consisting of 33 formulations with different additive ratios and a blank, was used to evaluate the performance of the four mixed additives. From each formulation, 200 micron-thick films were produced by the extrusion-blowing process. Samples from these films were submitted to accelerated UV aging, and the polymer degradation was measured by carbonyl group evolution, molecular weight distribution changes, and maximum elongation loss. The effect of the additive combination on the different degradation reactions is discussed qualitatively by using "relative variables" and a triangular diagram.