AML patients with normal karyotype comprise the largest subgroup ( approximately 50%) but have a highly heterogeneous clinical course. By multi-parameter flow cytometry we analyzed CD7 expression along with other phenotypic markers in 185 patients with normal-karyotype AML. CD7 was expressed in 68 (37%) patients. CD7 expression was associated with younger age (P=0.024) but not with sex, WBC count, or extramedullary disease. Patients expressing CD7 had significant shorter disease free (DFS) and post-remission survivals (PRS) than patients without CD7 (DFS of 12 months versus 42 months, P=0.005; PRS of 15 months versus 33 months, P=0.013). We also found that expression of CD34 or HLA-DR was associated with lower CR rate (P=0.0007 and P=0.019, respectively) but did not affect DFS or OS. Furthermore, as for all AML patients, we demonstrated that in the normal karyotypic subgroup, patients with higher WBC counts (>50) and older age (>60 years) had lower CR rate (P=0.003 and P=0.0157, respectively) and shorter OS (P</=0.001 and P=0.007, respectively). Multivariate analysis of age, WBC, CD34, HLA-DR and CD7 showed that CD7 expression was an independent risk factor for DFS (P=0.01) and PRS (P=0.02).