The process of neurite extension is complex and mechanisms involved probably vary depending on the local microenvironment (tissue site, extracellular matrix, neighboring cells, humoral factors, and developmental stage) of the developing or repairing neuron. Laminin contains at least one and perhaps more sites capable of stimulating process formation in a variety of neuronal cell types. This site contains a lysine and is likely located near a complex sugar residue. A complex of laminin and heparan sulfate proteoglycan appears to form a unique site with comparable activity, which is defined by monoclonal antibody recognition. Cell receptor complexes capable of recognizing the fibronectin cell attachment peptide RGD also bind laminin, while antisera to these complexes inhibit neurite outgrowth in some instances. The identification of laminin active sites and corresponding cell receptors could open new approaches to improving nerve regeneration in both the peripheral and central nervous system.