The TCR complex is a multisubunit complex, comprising at least eight transmembrane units. The clonotypic TCR alpha and beta chains are responsible for antigen recognition, whilst the invariant chains of the CD3 complex (delta, epsilon and gamma) and two zeta (zeta) polypeptides couple antigen recognition to downstream signal transduction pathways. TCRzeta (CD247) functions as an amplification module in the TCR signalling cascade and is also essential for the assembly and surface expression of the TCR/CD3 complex. Loss of TCRzeta expression is common in chronic infectious and inflammatory diseases, as well as in cancer. Previous work has indicated that TCRzeta(low)-expressing cells phenotypically resemble antigen-experienced effector T cells. Here, we describe the derivation of a flow cytometry-based TCRzeta expression index for the purpose of more precisely defining TCRzeta expression, in addition to utilising a simple transmigration assay in the demonstration that TCRzeta(dim) T cells have intrinsic migratory properties that may explain their accumulation at sites of inflammation.