Aplastic anemia, a disease caused by defective hematopoietic stemcells, is characterized by hypocellularity of the bone marrow andpancytopenia. Telomerase is a specialized ribonucleoprotein complex that isresponsible for the synthesis and maintenance of telomere repeats. It is anRNA-dependent DNA polymerase that synthesizes telomeric DNAsequences and almost universally provides the molecular basis for unlimitedproliferative potential. The aim of this work is to explore the telomeraseactivity and the association with the proliferative potential of hematopoieticstem cells in bone marrow in pediatric patients with aplastic anemia.Key words: