To investigate the expressions of proliferative antigen Ki-67 and apoptosis-antagonizing protein Bcl-2 in patients with chronic lymphocytic leukemia (CLL) and their clinical significance, immunohistochemistry method was used for detection of Ki-67 and Bcl-2 in bone marrow or peripheral blood of 29 patients with CLL. The results showed that the level of Ki-67 expression in advanced stage of CLL was higher than that in early stage of CLL and there was significant difference between these stages of CLL, but there was no significant difference between expression levels of Bcl-2 in two stages. The survival time in the group with Ki-67 expression < or = 8% was longer than that in the group of Ki-67 > 8%, and there was no significant difference of survival time between high and low groups in terms of Bcl-2 expression. It is concluded that detection of Ki-67 antigen and Bcl-2 protein for CLL patients can reflect the status of proliferation activity and apoptosis suppression of leukemia cells in patients; the level of Ki-67 expression closely correlate with the Binet stage and prognosis of CLL.