Cell scattering is used to describe the dispersion of compact colonies of epithelial cells induced by certain soluble factors such as growth factors, cytokines, and phorbol esters. The dispersal of epithelial colonies is a dynamic process usually initiated by membrane ruffling and centrifugal spreading of cell colonies. Subsequently, some cells within the colony begin to detach from their neighboring cells and exhibit a shape resembling that of motile fibroblasts. These cells continue to migrate, finally leading to a “scatter” phenomenon. Because the scattering of epithelial colonies possesses characteristics of epithelial-mesenchymal transition, such as the loss of epithelial cell-cell junctions and the acquisition of a motile mesenchymal cell phenotype, the scatter assay has been used for studying epithelial-mesenchymal transition and for detecting factors able to induce migratory behavior of cells. The method described in this chapter is intended specifically for measuring the scatter response of Madin-Darby canine kidney cells to hepato-cyte growth factor stimulation.