Several distinct cell adhesion molecule families have recently been identified and found to be important in the inflammatory response and for epithelial and endothelial homeostasis. The integrin family of adhesion molecules functions in both cell-matrix and cell-cell interactions, whereas the cadherins serve as important cell-cell receptors for maintenance of epithelial integrity. The leukocyte integrins, selectins, members of the immunoglobulin supergene family, and specific carbohydrates mediate adhesive interactions between leukocytes and endothelial cells. The mechanisms of leukocyte-epithelial adhesion are less well understood, but integrins and members of the immunoglobulin supergene family are also involved. The role of these molecules in pulmonary structure and inflammation is currently being actively explored. Further knowledge of these interactions, and the interplay of adhesion molecules, cytokines, and chemoattrac-tants is likely to lead to novel therapeutic modalities in inflammatory diseases of the airway and lung parenchyma. In this overview, the families of adhesion molecules will be summarized, and their relevance for pulmonary structure and inflammation will be discussed.