Integrins comprise the major class of receptors used by cells to interact with the extracellular matrix. Integrin/matrix interactions play a critical role in a variety of biological processes, including embryonic development, wound healing, tumor metastasis, cell growth and differentiation. It is now evident that integrins can transduce biochemical signals across the plasma membrane to the cell interior. Protein tyrosine phosphorylation has attracted much attention as an important regulator for integrin-mediated signal transduction. Recently, we have identified a novel signaling molecule, p130Cas, which participates in integrin-mediated signal transduction. p130Cas was originally identified as a protein hyperphosphorylated in cells expressing transforming gene products p47v-crk (v-Crk) and p60v-crk (v-Src). In this brief review, we will discuss about a role of p130Cas in signal transduction triggered by cell adhesion and transformation.