Recently developed major histocompatibility complex (MHC) multimer technologies allow visualization and isolation of antigen-specific T cells. However, functional analysis and in vivo transfer of MHC multimer-stained cells is hampered by the persistence of T-cell receptor (TCR) MHC interactions and subsequently induced signaling events. As MHC monomers do not stably bind to TCRs, we postulated that targeted disassembly of multimers into MHC monomers would result in dissociation of surface-bound TCR ligands. We generated a new type of MHC multimers, which can be monomerized in the presence of a competitor, resulting in rapid loss of the staining reagent. Following dissociation, the T cells are phenotypically and functionally indistinguishable from untreated cells. This 'reversible' T-cell staining procedure, which maintains the specificity and sensitivity of MHC multimer staining while preserving the functional status of T lymphocytes, may be of broad benefit for ex vivo investigation of T-cell functions and clinical applications.