The aims of the present work are to find the effect of gamma rays radiation at three doses in m Gy/h as radiation doses rate for 55 days at 7h/day irradiation on sex ratio of male and female rats. A significant decrease was noticed (p˂ 0.05) in the sum number of offspring, the number of male sex and male sex ratio when exposed to the doses from 0.06-0.4 m Gy/h and compared with control group. This decrease is proportional to the increase of doses gradually. Another point, the gamma ray radiations with mentioned doses rate and also with the same mating showed significant increases (p˂ 0.05) in the female offspring’s number and their sex ratio%. This increase is proportional to the increase of doses automatically. This paper also showed significant change in male and female rats sex ratio. The offspring female ratio % exposed to gamma ray was more than of the ratio% of offspring male rats compared with control, so during gestations, an exposure from any source with a frequency more than GHz .and wave length in (10-10 meter) must be avoided.