Endometrial cancer is the most common gynecologic cancer in the developed world. The cell-adhesion protein E-cadherin acts as a tumor-suppressor protein and is down-regulated by the transcription factor Snail, whose expression was shown to be associated with estrogen receptor signaling. This study aimed to investigate the expression of E-cadherin, Snail, and estrogen-receptor alpha in 87 primary tumors and 26 metastases of endometroid endometrial carcinomas. Reduced E-cadherin immunoreactivity was seen in 44.8% of the primary tumors and 65.4% of the metastases with a statistical correlation to higher tumor grade (P=0.003) only in metastatic lesions. About 28.7% of primary tumor specimens showed a positive Snail immunoreactivity that was correlated with reduced estrogen-receptor alpha expression (P=0.047). Positive Snail immunoreactivity was also seen in 53.8% of the metastases where it was correlated with higher tumor grade (P=0.003) and abnormal E-cadherin expression (P=0.003). Interestingly, a Snail expressing endometrial carcinoma-cell line showed a higher migration potential than a variant of this cell line with low levels of Snail. Taken together, our data are in line with a proposed role for Snail in endometrial tumor progression.