This study was purposed to investigate the megakaryocytic dysplasia and leukemia-associated phenotypes (LAP) of acute myeloid leukemia (AML) in the elderly. The megakaryocytic dysplasia, lineage infidelity, asynchronous antigen expression, total WBC count, and karyotypes were observed in the 147 none M(3)-AML patients. Logistic regression were used to analyzed the difference between the elderly (age > or = 60) and the control. The results showed that out of the total 147 patients (66 elderly patients, and 81 younger patients) 124 patients accepted induction chemotherapy, in which 70 cases achieved complete remission (elderly 18, younger 52, p = 0.008); megakaryocytic dysplasia was found in 32 patients (21.8%); CD33 and CD19/CD7 (lineage infidelity) was co-expressed in 55 patients (37.4%), CD34 and CD11b (asynchronous antigen expression) was co-expressed in 65 patients (44.2%); white blood cell count > 25 x 10(9)/L was found in 52 patients (35.4%). By the Logistic regression, compared with the control, in the elderly patients there was difference in the megakaryocytic dysplasia, and the co-expression of CD33/CD19/CD7 and CD34/CD11b (OR = 4.315, 2.761, 0.397; p = 0.001, 0.006, 0.020), but there was no difference in the total WBC count and karyotypes (OR = 0.802, 1.096; p = 0.646, 0.813). It is concluded that the incidence of megakaryocytic dysplasia, such as lineage infidelity, and asynchronous antigen expression, in elderly patients is higher than that in younger patients.