Abstract: Objective : To evaluate the effects of low dose and short-term domestic product of rhG-CSF in prevention and treatment of leukopenia caused by chemotherapy in children with malignancies. Methods : 34 children with malignancies were treated with combination chemotherapy. Each patient received three cycles of chemotherapy, namely, two trial cycles and one control cycle. In the control cycle, rhG-CSF was not used. In trail cycle one, rhG-CSF was used 48 hour after chemotherapy. In trial cycle two, rhG-CSF was administrated when white blood cell (WBC)<4x10⁹. The change of WBC and absolute neutrophil count (ANC) between different cycles was compared. Results : The duration of leukopenia and neutropenia in trial cycle one and trial cycle two was shorter than that in control cycle. However, trial cycle one showed better effect in prevention and treatment of leukopenia than that in trial cycle two. The lowest number of WBC and ANC in trial cycle one is higher than that in trial cycle two and control cycle (P<0.05). Conclusions : These results demonstrated that early treatment with low dose and short-term domestic product of rhG-CSF was able to shorten the duration of leukopenia and to alleviate the degree of leukopenia caused by chemotherapy.