Alveolar epithelial cells isolated from silica-treated rat lungs provide a system for the in vitro study of repair mechanisms. In studies of type II cell interactions with the extracellular matrix, we observed that type IIB pneumocytes from silica-treated rats adhered to tissue culture plastic more readily than do normal type II cells. This paper examines the adhesion characteristics of IIA and IIB cells and their modulation by divalent cations. We describe differences in the adhesive behavior of two subpopulations of freshly isolated type II pneumocytes from saline- and silica-treated rats. The observations have implications for repair and tissue remodeling in the lung.