Blasts showing hemophagocytosis have been very rarely reported in acute lymphoblastic leukemia. We report a pediatric case of B lymphoblastic leukemia (BLL) with t(12;21)(p13;q22); TEL-AML1 (ETV6-RUNX1) showing erythrophagocytosis and thrombophagocytosis by leukemic blasts. About 4% of the leukemic blasts in marrow aspirate smears showed phagocytosis of erythrocytes, platelets, or nuclear remnants in a 3-year-old Korean boy with a diagnosis of BLL. Conventional cytogenetics and molecular analysis revealed the presence of t(12;21)(p13;q22); TEL-AML1 (ETV6-RUNX1). The patient responded well to chemotherapy and is in a state of complete remission.