Antigen-specific T cells play a major role in mediating the pathogenesis of a variety of autoimmune conditions as well as other diseases. In the context of experimental autoimmune encephalomyelitis, a murine model of multiple sclerosis, we present here a general approach to the discovery of highly specific ligands for autoreactive cells. These ligands are obtained from a combinatorial library of hundreds of thousands of synthetic peptoids that is screened simultaneously against two populations of CD4+ T cells. Peptoids that recognize autoreactive T cells with extremely high specificity can be identified in the library. Since no specific knowledge is required regarding the nature of the native antigens recognized by the autoreactive T cells, this technology provides a powerful tool for the enrichment and inhibition of autoimmune cells in a variety of disease states.