Nucleopore filters coated with various genetic types of collagen and certain collagen-derived peptides were implanted under one margin of a skin wound on adult Notophthalmus viridescens (newt) hind limbs. In contrast to their behaviour on untreated filters, epidermal cells migrated readily and to equal degrees on human type I, newt type I, bovine type II, and bovine type IV collagen. Denaturation had no effect on the ability of collagen to support migration and all three cyanogen bromide peptides tested (alpha 1(I)CB3, 7 and 8) were able to support more migration than that seen on untreated filters. Glutaraldehyde-linked collagen gels supported migration but bovine serum albumin gels did not. These results show that there is no species or collagen-type specificity shown by newt epidermal cells as they migrate over collagen-coated substrates. They also demonstrate that the tertiary structure of the collagen molecule is unimportant in its ability to bind to newt epidermal cells, and that the alpha 1(I) chain has at least three, and probably many epidermal binding sites. Finally, they indicate that the improved migration on collagen is not a non-specific response to protein on the substrate.