Objective: To investigate the roles of Bcl-xl and Bcl-xs in the development and progression of endometrial carcinoma, and to explore their correlation.Methods: The expression of Bcl-xl and Bcl-xs in 32 cases of endometrial carci-noma, 12 cases of endometrial atypical hyperplasia, 6 cases of endometrial simple hyperplasia and 10 cases of normal en-dometrial tissues were examined by RT-PCR and Western-blot.Results: The expression of Bcl-xl mRNA and protein was significantly higher in endometrial cancer tissues than in normal endometrial tissues (P<0.05), and was statistically associat-ed with the pathological stage of endometrial carcinoma.(F=5.33, P=0.02).The expression of Bcl-xs mRNA and protein in atypical endometrial hyperplasia and endometrial carcinoma tissues were significantlly lower than that in normal endometri-al tissues (P<0.05), which was also associated with clinical stage and lymph node metastasis of endometrial carcinoma (P<0.05).The expression of Bcl-xl was negatively correlated with the expression of Bcl-xs in different endometrial tissues (r=-0.76).Conclusion: The abnormal expression of Bcl-xs and Bcl-xl was a factor for the pathogenesis and development of endometrial carcinoma.The negative correlation between Bcl-xl and Bcl-xs in different endometrial tissues as well as their relative expression ratio may have certain impact on the genesis of endornetrial cancer.