The present investigation was on Effect of Gamma irradiation on seed germination, seedling survival, lethal dosage LD₅₀ in Hibiscus sabdariffa L. The Hibiscus sabdariffa L. seeds were treated in a various dose of gamma irradiation 05KR, 10KR, 15KR, 20KR, 25KR, 30KR, 35KR, 40KR, 45KR and 50KR for studying the seed germination, seedling survival and lethal dosage LD₅₀. The seed germination was noted on 15^th day and the seedling survival was noted on 30^th day. Seed germination will be reduced when the dose of treatment increase. 50 percent of germination is considered as a LD₅₀ value. The LD₅₀ value was 20KR. The maximum value of seed germination was recorded in 05KR and the Minimum value was recorded in 50KR dose of gamma rays treatment.