Although γδ T cells are thought to participate in tumor immunosurveillance, little is known about their diversity in human cancers. Previously, we shown that γδ tumor infiltrating lymphocytes (TIL) may selectively infiltrate into human solid tumors and undergo activation. Here we compared γδ T cell receptor (TCR) repertoire and complementarity determining region (CDR3) size distribution in TIL, peripheral blood lymphocytes (PBL) and peritumoral tissue from 19 renal cell carcinoma (RCC) patients. We first analyzed Vδ gene segment usage by flow cytometry (FCM) using monoclonal antibodies (anti- Vδ–1 and Vδ2) and PCR using a panel of Vδ family specific oligonucleotide primers (Vδ1-Vδ6). We observed a small, however consistent decrease of γδ T cells in TIL comparing to autologous PBL. FCM analysis of Vδ usage showed decrease of Vδ2 and increase of Vδ1 subpopulation in TIL. Further, we studied clonal diversity of each particular Vδ family by CDR3 size analysis using run off PCR. A detailed analysis of CDR3 size distribution revealed striking differences between γδ TIL, PBL and normal tissue. γδ T cells at tumor site were found to present clonal expansions over a more or less complex polyclonal background. Our data show selective infiltration of γδ T cells into tumor tissue.