Radiolysis products from irradiated polyethylene resins were investigated using liquid chromatography coupled to photodiode array (PDA) and mass spectrometry (MS) detection. The resins were gamma-irradiated at applicable doses for food applications. The antioxidants and radiolysis products were extracted using accelerated solvent extraction (ASE) prior to analysis. Irgafos 168 and tris(nonylphenyl) phosphite (TNPP) were oxidized to form phosphate as the major product. Nonylphenol (from TNPP), and 2,4-di-tert-butyl phenol (from Irgafos 168) were also produced by the irradiation. Irganox 1076 formed a dehydrogenated product (loss of two hydrogens). The remaining detectable peaks had low responses suggesting low concentrations. Some of the low concentration products were tentatively identified using information from their fragmentation patterns in the MS/MS spectrum, and high mass accuracy measurements.