Abstract Effects of ionizing radiation on helium diffusion and desorption from LiNbO3 previously implanted with helium have been evaluated. The study has been performed for 45keV helium implanted samples for doses from 2×1015 up to 2×1017ions/cm2. The results show that the temperature for helium desorption decreases as the implantation dose increases. In order to study ionizing radiation effects, samples previously implanted with helium were irradiated with 1.8MeV electrons and the radiation-enhanced helium desorption was measured during irradiation at 500Gy/s. Ionizing-radiation-enhanced diffusion and redistribution of helium were observed to occur during electron irradiation. The helium-release behavior after 45keV implantation and after 1.5keV helium bombardment were compared.