The extracellular matrix (ECM) is a highly dynamic, elastic, and multicomponent compact structure which fills the space between cells and provides a storage site for growth factors and cytokines. The ECM undergoes constant remodeling, most obviously during development, wound healing, and other repair processes. Fibronectin (FN), a multidomain and multifunctional glycoprotein, is one ECM components which plays not only a structural role, but also a functional one, regulating the cell-ECM interaction. This review focuses on fibrillogenesis. The current state of knowledge about the molecular mechanisms which initiate FN binding to the cell surface through central and N-terminal FN sequences is described. It appears that exciting and drastic changes in the FN molecule's conformation are associated with fibril formation. Globular dimeric FN binds with an integrin receptor on the cell surface. FN-bound alpha5beta1 integrins actively translocate from focal adhesions to fibrillar adhesions and this movement causes stretching of the FN molecule. FN thus becomes extended and fibrillar and dynamic tension forces seem to unmask the cryptic self-association and other sites implicated in FN-matrix assembly. This provides for the formation of a fibrillar matrix network anchoring cells and molecules essential for signal transduction within the tissue. Finally, the molecular process of provisional matrix formation during wound healing is considered. There are some suggestions that modified FN preparations could be applied in medicine, particularly in patients after ischemic injury.