The ratio of Bcl-2 to Bax (Bcl-2/Bax) in 40 patients with acute myelogenous leukemia (AML) were determined. At the same time, the CFU-L of AML patients and drug resistance were detected by cell culture and MTT assay. The results showed that Bcl-2/Bax in AML was significantly higher than that in normal control (P < 0.001). Bcl-2/Bax ratio in colony growth group was higher than that in no-growth group (P < 0.05). Between drug resistance group and drug sensitivity group there was a significant difference in Bcl-2/Bax ratio (P < 0.05). There were more cases of drug resistance in high ratio group (H) than in low ratio group (L) (P < 0.05). Meanwhile, Complete Remission(CR) rate in group H was obviously lower than that in group L (P < 0.05) and patients in group H tended to have poor response. The above results indicated that the alteration of Bcl-2 and Bax is an important mechanism in the pathogenesis, progress and the development of drug resistance in AML. The determination of Bcl-2/Bax ratio has far-reaching implication in the treatment, choice of chemotherapeutic agents, and prediction of prognosis.