Prostate cancer micrometastasis allows cancer cells to vacate their original tumor sites and migrate to distant parts of the body via the bloodstream, lymphatic system, or by direct extension. Cells synthesize and secrete matrix metalloproteinases (MMPs) that degrade proteins of the surrounding extracellular matrix (ECM); thus allowing them to escape into the lymphatic or circulatory systems to invade other tissues. Transforming growth factor β (TGF-β) induces the migration and invasion of cancer cells and the expression of matrix metalloproteinases (MMPs), specifically MMP-2, and -9 in several malignancies. In this study, we examined the role of MMP-7, a known activator of MMP-2 and MMP-9, in TGF-β signaling in cell proliferation, migration, and invasion in prostate cancer cells. Basal expression levels of MMP7 mRNA, protein, and secreted protein were determined using RT-PCR, western blot analysis, and ELISA, respectively. Our data show that MMP7 mRNA and proteins were differentially expressed in several cell line models representing different stages of prostate cancer. TGF-β1 induces MMP-7 gene expression and protein levels 24 and 48 hours after treatment in PC3 cells. Our data also show that TGF-β induces cell migration and invasion in PC3 and E006AA cells; however, the selective knockdown of MMP7 expression using siRNA resulted in a significant decrease in control and TGFβ-induced cell migration and invasion in both PC3 and E006AA cells. MMP-7 knockdown also caused significant reduction in cell proliferation in PC3 cells. Our data suggest that MMP7 is essential for cell migration and invasion in prostate cancer cells indicating that it may be required for TGFβ-induced cancer metastases.