Abstract: 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 in32cases of endometrial carci -noma, 12cases of endometrial atypical hyperplasia, 6 cases of endometrial simple hyperplasia and 10cases 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 endometrial cancer.