Laminin, a large glycoprotein (Mr = 10(6)) and a major component of basement membrane, is shown here to be a potent chemoattractant for human gingival epithelial cells. Laminin stimulated chemotaxis and chemokinesis of gingival epithelial cells in the modified Boyden chamber assay. This effect appeared to be laminin receptor mediated. Gingival epithelial cells were shown to bind laminin (Kd = 2.0 nM) with 10,000 to 30,000 binding sites per cell. Antilaminin antibody, which inhibited laminin binding, inhibited the chemotactic response of epithelial cells to laminin, while antifibronectin was without effect. Fibronectin was not as potent a chemoattractant as laminin. Other biological response modifiers were also tested; of these, Type IV collagen and epidermal growth factor were active as chemoattractants, although not as effective in inducing chemotaxis as laminin. The data indicate that laminin and other components of basement membrane may be important in regulating the migration and growth of gingival epithelial cells.