The aim of study was to investigate the immunophenotype characteristics and prognosis of acute leukemia patients with cross-expressing lymphoid and myeloid lineage-associated antigens. The immunophenotypes of leukemic cells were examined by using flow cytometry. All patients were classified into several groups according to FAB subtypes and immunophenotyping. The cross-expressed antigens analyzed for AML included CD2, CD7, CD19, CD56 and other co-expressed lymphoid antigens. The myeloid antigens analyzed for ALL included CD13 and co-expressed CD13/CD33. ALL and AML patients without expression of cross-expressing antigens were selected as control. Complete remission (CR) ratio and relapse-free survival (RFS) of patients in all groups were compared. The results indicated that among 161 patients analyzed, 91 cases of AML with cross-expressing lymphoid and myeloid antigens included that 24 cases of AML expressed lymphoid surface marker-CD7, namely CD7(+) AML, 14 cases of AML only expressed lymphoid surface marker-CD19, namely CD19(+) AML, 8 cases of AML expressed lymphoid surface marker-CD2 (including CD2/CD19 co-expressed), namely CD2(+) AML, 10 cases of AML expressed lymphoid surface marker-CD56 (including CD56/CD19 or CD56/CD2 co-expressed), namely CD56(+) AML, 16 cases of AML expressed two or more lymphoid surface markers, namely Ly ≥ 2(+) AML, 9 cases of ALL expressed myeloid surface markers CD13, namely CD13(+) ALL, 10 cases of ALL expressed myeloid surface markers CD13 and CD33, namely CD13/CD33(+) ALL. 29 cases of ALL did not expressed myeloid surface markers, namely My(-) ALL, and 41 case of AML did not expressed lymphoid surface markers, namely Ly(-) AML. CR ratio and RFS of Ly ≥ 2(+) AML patients were lower than those of Ly(-) AML patients. RFS of CD56(+) AML patients was lower, but CR ratio had no significant difference, when compared with Ly(-) AML patients. CR ratio and RFS of other AML patients with cross-expressing antigens had no significant difference when compared with Ly(-) AML patients. CR ratio and RFS of CD13(+) ALL and CD13/CD33(+) ALL patients had no significant difference when compared with My(-) ALL patients. It is concluded that the importance of cross-expressing antigens for prognosis of patients should be analyzed concretely. CD56(+) AML and Ly ≥ 2(+) AML have bad prognosis, while other cross-expressed lymphoid and myeloid lineage-associated antigens have no impact on prognosis of acute leukemia patients.