Eggs (1, 2 and 3-day-old), larvae (early and late) and 4-day-old pupae of the rice moth, Corcyra cephalonica (Stainton), were treated with 60Co gamma-radiation at doses from 0 to 100 krads. Evaluation of moth radiosensitivity by the survival of treated eggs, larvae and pupae led to the following sequence of stages in order of increasing radioresistance: for the eggs, 1, 2 and 3-day-old; for larvae and pupae, early larvae (5 days after hatching), late larvae (5 days before pupation) and 4-day-old pupae. Twenty five kiloradians was found to be the most likely unit for disinfestation by radiation of C. cephalonica.