The effect of Xrays on adults of Sitophilus zeamais Motschulsky was studied in order to improve the irradiation treatment of stored food. Xrays had a significant effect on the activity, mortality and fertility of this insect pest. Radiation levels over 70 Gy can achieve 100% adult mortality after 48 days. For practical purposes, 200 Gy can be regarded as a suitable lethal dose for eradicating S. zeamais adults and 100 Gy for preventing F1 production.