Adhesion molecules participate in a broad variety of biological processes, i.e. tumor progression and inflammation, through their involvement in cell-to-cell interactions and immunoinflammatory cell migration. This review describes the basic properties of adhesion molecules with reference to inflammatory bowel disease and colorectal carcinoma. Accumulating data suggest that adhesion molecules could be pathogenetically pertinent to other gastrointestinal disorders such as celiac disease (nontropical sprue) and gastroduodenal ulcer. Future therapeutic approaches in inflammatory and malignant disorders may possibly be development of principles targeting adhesion molecules.