This study was conducted to examine the effects of 0.3-Mrad irradiation on growth and toxigenicity of Clostridum botulinum types A and B on chicken skins. Irradiation followed by aerobic or anaerobic incubation at 30°C extended the shelf life of skin samples and delayed growth and toxin production by C. botulinum. During 2 weeks of incubation at 10°C, the irradiated and nonirradiated C. botulinum spores failed to grow or produce toxin.