Irradiated polyamide-1010 (PA1010) with and without heat treatment after γ-ray irradiation was compared by wide angle x-ray diffraction (WAXD), differential scanning calorimeter (DSC) and the determination of gel fractions. The results indicate that post radiation effects due to post radiation crosslinking and scissions affect physical properties. Post radiation effects restrain the formation and perfection of the planes (010), and make the crystals imperfect. Post radiation effects change the crystalline structures of polyamide-1010.