The RIE-1 cell line is an untransformed, epithelial cell line derived from the rat small intestine. We report that epidermal growth factor (EGF), which regulates the proliferation of RIE-1 cells, also directs their movement. We measured cell migration through gelatin-coated filters in blind-well Boyden chambers. The migration of RIE-1 cells was stimulated up to approximately 100-fold by EGF, with a half-maximal response at 1-2 ng/ml and a maximal effect at 10 ng/ml. Further analysis showed that the RIE-1 cells responded directionally to a gradient of EGF in solution. Other growth factors tested did not stimulate RIE-1 cell migration, and EGF did not stimulate the migration of fibroblasts in this assay. We conclude that EGF is a potent and specific chemo-attractant for RIE-1 intestinal epithelial cells and suggest that EGF might influence epithelial cell migration in vivo.