Objective: Endometrioid adenocarcinoma is the most common pathological type of endometrial carcinoma. This study aimed to examine the expression of PTEN and CD146 in endometrioid adenocarcinoma, and to investigate their relationship with clinical characteristics of endometrioid adenocarcinoma. Materials and Methods: The expression of PTEN and CD146 in 126 specimens of endometrioid adenocarcinoma was detected by immunohistochemical technique, and the correlation of their expression with clinical parameters of the patients was analyzed. Results: PTEN expression in endometrioid adenocarcinoma group was lower than that in endometrial hyperplasia group and endometrial polyp group, while CD146 expression in endometrioid adenocarcinoma group was higher than that in endometrial hyperplasia group and endometrial polyp group (p < 0.05). High expression of CD146 was associated with his tological grade and depth of invasion of endometrioid adenocarcinoma, but there was no correlation between PTEN expression and clinical parameters. Conclusions: CD146 and PTEN may be promising biomarkers and targets for the diagnosis and treatment of endometrioid adenocarcinoma.