There is a growing body of evidence suggesting that alterations in the adhesion properties of neoplastic cells may play a pivotal role in the development and progression of bladder cancer. Loss of intercellular adhesion and the desquamation of cells from the underlying lamina propria allows malignant cells to escape from their site of origin, degrade the extracellular matrix, acquire a more motile and invasive phenotype, and finally invade and metastasize. In addition to participating in tumor invasiveness and metastasis, adhesion molecules regulate or significantly contribute to a variety of functions, including signal transduction, cell growth, differentiation, site-specific gene expression, morphogenesis, immunologic function, cell motility, wound healing, and inflammation. To date, a diverse system of transmembrane glycoproteins have been identified that mediate the cell-cell and the cell-extracellular matrix adhesion. The main families of adhesion molecules are the cadherins, integrins, members of the immunoglobulin superfamily, and selectins. We review the recent data regarding the role of selected adhesion molecules in the pathogenesis of bladder cancer and their clinical exploitation as biomarkers of this malignant disease.