Abstract: A study of cyclo-polyphenylacetylene before and after γ-irradiation from infrared spectrum, ultraviolet spectrum and NMR show that there is no difference in chemical structure between the samples irradiated by γ-rays to 1.4 × 109 rad and non-irradiated ones and moreover there is no change in intrinsic viscosity, determined by viscosimetry. It seems that cyclopolyphenylacetylene is an irradiation resistance material.