Newly emerged adults of the European grapevine moth, Lobesia botrana (Denis and Schiffermuller) (Lepidoptera: Tortricidae), were irradiated with various doses of gamma radiation and crossed to unirradiated counterparts of the opposite sex. Fecundity was decreased when unirradiated females were mated with either 300- or 350-Gy-irradiated males. Adult males that were irradiated with 400 Gy and mated with unirradiated females retained a residual fertility of 2.7%. The radiation dose at which irradiated females were found to be 100% sterile when mated with unirradiated males was 150 Gy. The inherited effects in the F₁ progeny of irradiated male parents were examined at 100, 150, and 200 Gy. Fecundity and fertility of the F₁ progeny of males irradiated with 150 Gy and inbred or crossed with irradiated and unirradiated moths were also recorded. A significant reduction in fertility was observed when F₁ males mated with either F₁ or unirradiated females. According to sterility index, F₁ females who mated with F₁ males had greater sterility than when F₁ females were crossed to 150-Gy-irradiated males. Based upon the results of this study, 150 Gy of gamma radiation would be the optimal dose to use in a sterile insect technique and F₁ sterility program against L. botrana.