Transient remissions (TRs) of acute leukemia without any antileukemic treatment are extremely rare events. We report 2 TRs of acute lymphoblastic leukemia and acute myeloid leukemia in a 2-year-old boy and a 12-year-old girl, respectively, both associated with red blood cells and platelets transfusions and infection. These 2 factors are frequently present in previously reported cases and could induce a stimulation of the immune system although the underlying mechanisms of TRs are still unknown.