Objectives : To assess the serum level of macrophage inflammatory protein -1-α (MIP-1- α ) in patients with bone marrow aplasia including acquired aplastic anemia, Fanconi's anemia and pure red cell aplasia, and to study its relations to disease severity , different laboratory parameters and response to therapy. Methodology :- Assessment of serum level of MIP-1- α was done by enzyme linked immunosorbant assay (ELISA) in 39 patients with bone marrow aplasia, 10 patients with chronic hemolytic anemia as a patient control group and 15 age matched normal healthy control. Results : Results of the study were analyzed by appropriate statistical methods and showed that there is significant difference between BMF patients and control groups either CHA or normal control regarding MIP-1-α serum level which tends to be higher in BMF patients. Among the different 3 subgroups pf BMF patients, MIP-1- α level in AAA patients was higher than FA and PRCA. Also MIP-1- α level tends to be higher among newly diagnosed cases of BMF, either AAA or FA than among patients who received treatment. However, it was noticed to be higher in patients who responded to treatment than those who didn't respond. The correlations study revealed that, there is +ve correlation between MIP-1- α level and each of the TLC of FA patients, the reticulocyte count of AAA patients and the TLC of patients who responded to treatment, either AAA or FA. Conclusion : Elevated serum level of MIP-1- α in pediatric patients with bone marrow failure (BMF) documenting the important pathogentic role of this chemokine in BMF.