Integrin receptors mediate cell-cell and cell-extracellular matrix (ECM) interactions in many different cell types, including neuronal cells. Earlier studies have shown a clear role for integrins in axon extension and cell adhesion/migration in CNS inflammation. Here we summarize more recent work that shows integrin functions in many phases of neural development, from neuroblast migration to synapse formation. Integrins of the beta-1 and alpha-v family are widely expressed on neurons at many stages of development, and their activity is regulated. Integrins are also important in the adult nervous system, since they have been implicated in synaptic plasticity involved in memory and learning. In addition, several diseases of the nervous system appear to involve beta-1, beta-2, and alpha-v integrins on leukocytes and glial cells. Research challenges for the future include understanding functions of specific integrin heterodimers and identifying the relevant integrin ligands that function in the nervous system.