The role of Eps8 in human breast cancer was studied, and we found that Eps8 was overexpressed in >60% of human breast cancer samples compared with adjacent normal breast tissues by immunohistochemical analysis. Eps8 was highly expressed in the highly invasive breast cancer cell line MDA-MB‑231 compared with the weakly invasive breast cancer cell lines MCF7 and MDA-MB‑468. MCF7 cell line stably expressing Eps8 was established by G418 screening, and the ectopic expression of Eps8 enhanced MCF7 breast cancer cell growth and survival as assessed by MTT analysis, cell viability and liquid colony formation, whereas the lentiviral expression of Eps8 shRNA in MDA-MB‑231 cells resulted in a significant reduction in cellular growth and proliferation in vitro and in vivo. Furthermore, Eps8 knockdown inhibited breast cancer cell migration in wound healing assays, decreased the number and size of EGF-induced filopodia and increased the sensitivity of breast cancer cells to cisplatin analyzed by MTT assays. Eps8 knockdown decreased the levels of phosphorylated extracellular signal-regulated protein kinase (ERK) and MMP9 but increased p53. Moreover, Eps8 knockdown suppressed a partial EMT-like transition and showed a significant increase in E-cadherin and decrease in N-cadherin and vimentin. These results suggest that Eps8 is overexpressed in human breast cancers, possibly by regulating ERK signaling, MMP9, p53 and EMT-like transition to affect breast cancer cell growth, migration and invasion. Therefore, Eps8 might represent a novel potential target in human breast cancer therapy.