Aim of the work: this study evaluated the efficacy of bone marrow (BM) transplantation to protect male rats from dangerous effect of multi-walled carbon nanotubes (MWCNTs) or/and γ-irradiation on the hematopoietic and lung tissues. Materials and methods: experimental animals were divided into 8 groups each consist of 6 male albino rats. Control group, BM-injected group, MWCNTs-injected group, 5Gy γ-irradiated group, 5Gy γ-irradiated+ MWCNTs-injected group, MWCNTs-injected+ BM-injected group, 5Gy γ-irradiated+ BM-injected group and 5Gy of γ-irradiated+ MWCNTs-injected + BM-injected group. All the treated animal groups were sacrificed after 28 days of the treatments. Blood components, MDA and GSH levels in the lung tissue were analyzed. The histopathological study in the lung tissue was also recorded. Results: exposure to MWCNTs or/and γ-radiation induced a significant decrease in certain blood components (WBCs, RBCs, Hb content, HCT value and PLT count). Furthermore, a significant elevation in MDA level and a significant decrease in GSH content were detected in the lung tissue. The histopathological changes after exposure of rats to MWCNTs recorded perivasculitis, atelectasis and interstitial pneumonia. Also, γ-radiation represented more collapsed and thickened walls in the alveoli, thickened bronchiolar walls with partial epithelial lining and foci of pulmonary hemorrhage in the lung tissue. The effect of BM transplantation after MWCNTs or/and γ-radiation ameliorated the values of blood components, MDA and GSH levels in the lung tissue. The improvement occurred by BM transplantation in rats treated with MWCNTs or/and exposed to γ-radiation were also recorded. The lung tissue showed numerous alveoli with thin interalveolar septa, alveolar sacs and terminal bronchioles with highly folded mucosa. Conclusion: treatment with BM transplantation improved the most deleterious parameters obtained in the blood and lung tissue of MWCNTs exposed or/and γ-irradiated rats.