[en] Effects of gamma radiation on eggs, larvae, pupae and adult stages of the cigarette beetle were studied. The LD₅₀ and LD₉₉ of gamma radiation to the eggs (7±1 days) were 327 Gy and 834 Gy respectively on the 3^rd day after irradiation. At 300 Gy the eggs were able to hatch but died in the pupal stage. None of the eggs hatched when treated with 800 Gy and other doses. The LD₅₀ and LD₉₉ to the last instar larvae (7±1 days) were 505 Gy and 1,547 Gy on the 12^th day after irradiation. The mortality of last instar larvae varied directly with the irradiation dose, no larvae could survive when irradiated at 1,500 Gy and above. At the dose lower than 1,200 Gy, some pupation was observed but no adult emergence occurred. The LD₅₀ and LD₉₉ of gamma radiation to pupae (4±1days) were 548 Gy and 1,578 Gy on the 12^th day after irradiation. The pupal mortality varied directlty with the dose. No adult emergence was obtained after irradiated at 1,500 Gy. At 300 Gy, the adults emerged with deformity and sterility. The LD₅₀ and LD₉₉ to adults (3±1 days) were 931 and 1,746 Gy respectively on the 12^th day after irradiation. The mortality of adults increased when irradiated at higher dose and none of the eggs hatched after treated adults with 300 Gy. The dosage of 300 Gy was high enough to inhibit the development of all stages. Melanization occurred in untreated young larvae after killing by freezing. Some parts of larval body became dark brown to black while the rest of the body was yellow-white or greyed-yellow. In the treated young larvae, non-melanization to slight melanization occurred at 100, 300 and 500 Gy. The degree of melanization in treated young larvae decreased with the increasing doses. In treated old larvae, the melanization increased with the increasing doses