Objective: This study was to observe the levels of Ets2 mRNA expression in leukemia patients and investigate the effect of small interfering RNA (siRNA) targeting Ets2 gene on sensibility of human acute monocytic leukemic cell line SHI-1 cells to etoposide (VP-16). Methods: Ets2 mRNA levels were determined by reverse transcription polymerase chain reaction (RT-PCR). After the transfection of Ets2 siRNA to SHI-1 cells by electroporation method, qRT-PCR was used to detect Ets2 gene expression in these cells; VP-16-induced apoptosis was investigated by Annexin V-FITC/PI. Results: Est2 mRNAwas detectable in SHI-cells. The Est2 expression rate was respectively 10% in 5 healthy volunteers, 60% in 5 acute lymphocytic leukemia (ALL) patients, 73.68% in 19 acute nonlymphocytic leukemia (ANLL) patients and 100% in 4 chronic myeloid leukemia (CML) patients. The expression levels of Ets2 mRNA were significantly higher in leukemia patients compared with healthy volunteers. It also showed that siRNA targeting Ets2 gene resulted in substantial loss of Ets2 mRNA of SHI-1 cells compared to the control groups. Downregulation of Ets2 gene expression increased SHI-1 cells apoptosis and VP-16-induced apoptosis of SHI-1 cells. Conclusion: The high-level expression of Ets2 transcription factor in leukemia cells were connected with proliferation and anti-apoptosis of leukemia cells. SiRNA mediated Ets2 gene silencing induced cell apoptosis and enhancedin vitro sensitivity to chemotherapy (VP-16) of SHI-1 cells. It speculated the high-level expression of Ets2 may actuallybe an unfavorable determinant of chemotherapy sensitivity in leukemia.