We report the clinical, cytological, immunophenotypic, and cytogenetic findings in one patient with acute erythroblastic leukemia. Blast cells were identified by their reactivity with the early erythroid antibodies FA6-152 and carbonic anhydrase I. The leukemic blasts had no specific differentiating features identifying them as erythroblasts even at an ultrastructural level. Cytogenetic studies revealed multiple chromosome aberrations: 45,XX,i(11q),-16,-17,-21,+der(21)t(21;?)(q22;?),+mar 1.