Abstract: Background and Objectives: The damaging effects of ionizing radiation lead to cell death. The present study was performed to assess the possible ameliorating effects of bone marrow transplantation (BMT) on the histopathological and histochemical changes in the kidney tissue of γ-irradiated pregnant rats and their fetuses. Materials and Methods: Pregnant rats were divided into 5 sets (6 females in each set): Group C (untreated pregnant rats), group R7 (pregnant rats exposed to 2Gy of γ-rays on the 7th day of pregnancy), group R7+BM (pregnant rats exposed to 2Gy of γ-rays on the 7th day of pregnancy then injected by freshly BMT (75×106±5 cells) intra peritoneally after 1 h of irradiation, group R14 (pregnant rats exposed to 2Gy of γ-rays on the 14th day of pregnancy), group R14+BM (pregnant rats exposed to 2Gy γ-rays on the 14th day of pregnancy and after 1 h received 1 dose of BMT). All pregnant rats were sacrificed on the 20th day of pregnancy and kidney samples of pregnant rats and their fetuses were removed for histopathological and histochemical studies. Results: Gamma rays caused many histological and histochemical deviations in the kidney tissue of mothers and their fetuses on day 7 or 14 of gestation, but bone marrow transplantation highly improved the damage were occurred due to γ-rays. Conclusion: Bone marrow transplantation has the ability to decrease the injury of gamma rays.