ER beta 1 is a member of the nuclear receptor superfamily of ligand-regulated transcription factors. It plays an important role in regulating the progression of breast cancer. However, the mechanisms of ER beta 1 in tumorigenesis, metastasis and prognosis are still not fully clear. In this study, we showed that the expression of ER beta 1 was positively correlated with E-cactherin expression in breast cancer cell lines. In addition, we found that ER beta 1 upregulates E-cadherin expression in breast cancer cell lines. Furthermore, we also found that ER beta 1 inhibits the migration and invasion of breast cancer cells and upregulated E-cadherin expression in a Id1-dependent manner. Taken together, our study provides further understanding of the molecular mechanism of ER beta 1 in tumor metastasis and suggests the feasibility of developing novel therapeutic approaches to target Id1 to inhibit breast cancer metastasis. (C) 2014 Elsevier Inc. All rights reserved.