Objective: To evaluate the effect of prolactin (PRL) on the migration of MCF-7 breast cancer cells and the expression of E-cadherin. Methods: We used the wound healing assays to evaluate the migration of MCF-7 cells and the Western blot technique to evaluate the expression of E-cadherin. Results: The results show that PRL produced an increase in the migration of MCF-7 cells without inducing a reduction in the expression of E-cadherin. Conclusions: Prolactin significantly increased the migration of MCF-7 breast cancer cell line without inducing an epithelial-mesenchymal transition (EMT), which could be related to a collective type of migration.