The analysis of the Tcell receptor (TCR) Vb repertoire is one of the most sensitive methods to identify the clonal expansion T cells which respond to tumor associated antigens. Recently, studies have focused on clonally expanded Tcells from patients or normal donors induced by leukemia associated antigens in vivo or in vitro. Understanding such clonality and restricted usage of TCR Vβ repertoire of leukemia-associated expanded T cells may be useful for the design of new immunotherapeutic strategy for leukemia.