Infiltration of leukocytes into the bowel wall is a landmark of the inflammatory bowel diseases (IBD) ulcerative colitis (UC) and Crohn's disease (CD). The leukocyte movement is dependent on physical contact (adhesion) between the leukocytes and activated endothelial cells and can be divided into capturing, rolling, leukocyte flattening, and extra-vasation. The molecules shown to form the basis of leukocyte-endothelial binding are referred to as cell adhesion molecules (CAMs). Several of these molecules have additional properties, including interaction between leukocytes and proteins in the extracellular matrix, collaen in basement membranes, and stromal cells in lymphoid tissue and bone marrow. Furthermore, studies have indicated that CAMs interfere with the tumor cell's ability to metastasize. This paper will focus on a description of those CAMs that are either known or believed to be involved in the pathogenesis of IBD. Investigations of the presence and functions of these CAMs in IBD is reviewed, and potential new treatments are discussed.