Leukemias account for 30% of all malignancies. There are 2 main groups of leukemias in children: lymphoblastic leukemias which represent approximately 85% of cases and myeloblastic leukemia, which is rarer. Initiated in the 1970s, multidrug therapies make it possible to cure 80% of children with acute lymphoblastic leukemia. A bone marrow transplant, which makes it possible to replace the damaged bone marrow following the disease, or even by the treatments, can also be proposed. However, the disparities remain high and the consequences heavy. Acute myeloblastic leukemias have a cure rate of about 50%, while some infant leukemias have a very poor prognosis.