Tumor cell metastasis is a complex, multi-step process that is a major cause of death and morbidity amongst cancer patients. Cell adhesion plays a critical role in the development of metastatic cancer, and it is mediated by interactions between receptors on the cell surface and ligands of the extracellular matrix or other surfaces. Therefore, inhibition of the cell adhesion process appears to be an effective method of preventing metastasis. This work describes a genetically engineered polypeptide with the potential to prevent cell adhesion and inhibit metastasis. We have found that the cell penetrating peptide Tat, fused with elastin-like polypeptide (ELP) inhibited adhesion, spreading, invasion and migration of SKOV-3 ovarian cancer cells in cell culture. Furthermore, we have also confirmed that Tat-ELP has anti-metastatic potential in an experimental ovarian cancer metastasis model in vivo, causing approximately 80% reduction in the tumor burden. Since cell attachment is an important step in tumor cell invasion and metastasis, these results suggest a novel role of Tat-ELP as a therapeutic intervention in cancer metastasis.