Abstract: Objective: To investigate the abnormal expression and clinical significance of cell division cycle 6 (CDC6) in adult patients with acute leukemia. Methods: The expression level of CDC6 mRNA was detected in peripheral blood of acute leukemia patients with non-remission (NR) or complete remission (CR) and normal patients using nested RT-PCR. Results: The rate of positive expression of CDC6 was 27.66% in the control group, 56.25% in the acute leukemia with CR group and 100% in the acute leukemia with NR group. Statistical analysis showed that the rate of positive expression for CDC6 in the control group was significantly lower than in the other groups (P<0.05), while that in the leukemia with NR group was significantly higher than in the acute leukemia with CR group (P< 0.05). Conclusion: CDC6 mRNA expression contributes to the high proliferative activity in acute leukemia cells. Abnormal expression of CDC6 may serve as a marker for monitoring the state of illness in adult acute leukemia patients.