Leukemia has been recognized since 1845, when a report was published on a patient who died of the disease which have shown an amplified number of blood cells. Twenty years later it was found that diagnosis of leukaemia could be possible through bone marrow puncture. Leukaemia is one of the most common types of cancer worldwide. Leukaemia is a heterogeneous group of malignancies, broadly divided into acute and chronic leukaemia with further sub-classification into lymphoid and myeloid varieties. Decrease in incidence of infectious diseases and increased human life span caused prevalence of leukemia. Leukemia is diagnosed 10 times more often in adults than in children and more common in males than females.