Discerning the mechanisms by which leukocytes gain access to organ allografts is crucial to our understanding of the immunologic basis of organ allograft rejection. Adhesion molecules play prominent roles in all phases of the rejection process. Recent studies have provided detailed insights into the adhesive interactions that guide T cells from the site of activation within secondary lymphoid organs to the graft site. The downstream events, however, by which lymphocytes interact with the functional components of organ allografts, which are predominantly epithelial in origin, are obscure and represent a gap in our understanding of the immunologic basis of allograft rejection. One such interaction involves CD103, a T-cell integrin that recognizes the epithelial cell-specific adhesion molecule, E-cadherin. The focus of this review is to analyze the role of adhesion molecules in lymphocyte trafficking to organ allografts, with specific emphasis on the role of CD103.