Objective: To investigate whether bcl-2 directly contributes to the development of drug resistance and apoptosis in o- varian cancer cell lines cells OC3. Methods: Retrovirus expression cector pLXSN-bcl-2 was constructed and was transfected to ovarian cancer cell line cells OC3 using Lipofectin,with empty vector pLXSN as a control. bcl-2 expession of transfected cells was analyzed by FACS and Western blot and Adr-induced cytotoxicity was measured by MTT assay. Apoptosis was also detected by PI DNA staining and DNA Ladder analysis.Results:pLXSN/bcl-2 transfected cells OC3/bcl-2 overexpressed bcl-2 and were resistant to Adr-induced cytotoxicity.The ability against Adr-induced apoptosis was increased. Conclusion: bcl-2 may play an important role in the resistance to Adr-inducing apoptosis, thereby increasing resistance of OC3/bcl-2 cells to chemotherapy.