Background: Bone marrow failure is a group of disorders characterized by the inability of bone marrow to produce sufficient blood cells. They can be divided into inherited disorders, acquired disorders and diseases infiltrating bone marrow. Acute leukemia is a serious cause of bone marrow failure which  needs early diagnosis and management . Purpose: To study for   registry,  and clinical spectrum of bone marrow failure in Beni-Suef university hospital to detect the magnitude of the problem . Patients and methods: It is  cross sectional study over a period of six months from January 2019 to June 2019, in which patients with bone marrow failure (monocytopenia, bicytopenia or pancytopenia) from  pediatric age group (0-13 years) who were admitted in the pediatric department in Beni-Suef university hospital were included and followed up. They were subjected to a detailed history, full examination and laboratory investigation; complete blood count, reticulocyte cont, bone marrow aspirate & biopsy,  virology study and accordingly other investigations were done such as flow cytometry for cd55 & cd59, glucocerebrosidase enzyme assay, chromosomal breakage analysis and imaging. Results: Out of 22000 outpatients and 1700 inpatients,55 patients had diagnosed as bone marrow failure during six months duration with percentage of o.23%. The most frequent diagnosis of bone marrow failure was acute Leukemia (30.9 %), followed by Idiopathic aplastic anemia (27.3%) then Fanconi anaemia (21.8%). Conclusion: Bone marrow failure is not rare ,acute Leukemia should be considered strongly in the diagnosis of any case of bone marrow failure.