In vivo and in vitro experiments have demonstrated that the retinal pigmented epithelium can give rise to neuronal precursors during retinal regeneration in amphibians. In vitro experiments have further demonstrated that this process is greatly facilitated by two molecules associated with basement membranes: laminin and fibroblast growth factor. We now report that retinal regeneration can be blocked in vivo by an antibody that inhibits the interaction of cells with the laminin-heparan sulfate proteoglycan complex. These results further support a role for the extracellular matrix in regulating cellular phenotype during retinal regeneration.