Pancytopenia is a medical condition in which there is a reduction in the number of red and white blood cells, as well as platelets. It is not a disease, but a triad of findings that may result from a number of disease processes.Causes of Pancytopenia are Familial Hemophagocytic Syndrome, Aplastic anemia, Dyskeratosis congenita, Myelodysplastic syndrome, Leukemia, Leishmaniasis, Severe Folate or Vitamin B12 deficiency, Systemic Lupus Erythematosus, Paroxysmal nocturnal hemoglobinuria, overwhelming viral infections, Alimentary Toxic Aleukia, copper deficiency, pernicious anemia, medication and hypersplenism.This study included eighty five patients presenting with pancytopenia, their age ranged from 1 year to 75 years, the median age was 43, they were 50 males and 35 female, these patients were attending the National Cancer Institute (Cairo University) and Nasser Institute (Ministry of Health). And according to their history, clinical examination and Lab investigations as (peripheral blood, bone marrow aspirate, bone marrow biopsy, cytochemistry, cytogenetics and immunophenotyping), we reached the final diagnosis as follows .