[en] Objective: To observe the effects of prenatal irradiation on functions of haematopoietic stromal cells. Methods: Long-term effects of 2.0Gy ¹³⁷Cs γ-radiation at midterm gestation of mice on the haematopoietic stromal cells of their offspring were studied. Results: The quantity of femoral bone marrow nucleated cells (BMNCs) in the irradiated offspring was markedly lower than that of the normal offspring (P < 0.01). And stromal expressions of the growth factors, granulocyte-macrophage colony-stimulating factor (GM-CSF) and stem cell factor (SCF), of the irradiated offspring were higher compared with those of the normal offspring (P < 0.05). At the same time, the ability to support hematopoiesis by the stromal cells in irradiated offspring was higher than that in normal offspring. Conclusion: The results suggest that irradiation with 2.0Gy ¹³⁷Cs γ-rays is sufficient to produce measurable effects on developing murine haematopoietic stromal cells