Cell adhesion molecules have been recognized to play a major role in a variety of physiological and pathophysiological phenomena, such as embryogenesis, maintenance of tissue architecture and tissue damage repair, recruitment of leukocytes into tissues, immunological reactions requiring cell-to-cell contact. Their role in inflammatory reactions is crucial, in particular their involvement in allergic inflammation has been extensively studied. It has become apparent that the expression patterns and cell localization of certain adhesion molecules are related to the dynamic of allergic inflammation, and specifically to selective migration of eosinophils and interactions with epithelial cells of the target organs. In some instances, cell adhesion molecules by themselves may be regarded as reliable markers for clinical purposes. In addition, the pharmacological modulation of expression and release of adhesion molecules may provide new insight about the mechanisms of action and effectiveness of antiallergic drugs.