Although the mechanisms that determine TCR-αβ V gene repertoire are well studied, the genetic influences involved in TCR-γδ repertoire development are unclear. Unlike the TCR-γδ populations that localize in epithelial tissues, the circulating peripheral TCR-γδ V region repertoire is quite diverse. Previous studies have shown that three TCR-γ chains and at least six TCR-Vδ genes are expressed by splenic TCR-γδ cells. However, the relative frequency of individual γδ subsets among genetically diverse mice has not been determined. Therefore, the repertoire of TCR-γδ cells was examined using anti-TCR V region specific mAb against Vγ2 and Vδ4 on TCR- γδ+ cells from total splenocytes. We found that there was a strain- specific variation in TCR-γδ usage. The frequency of Vγ2 expression in different strains varied from 54 to 12%, and the frequency of Vδ4 expression in different strains varied from 38 to 10%. However, the level of Vδ4 and Vγ2 expression for an individual strain was highly consistent from experiment to experiment. F1 analysis between parental strains that differed in relative frequency of either Vγ2+ or Vδ4+ cells revealed that high expression was genetically dominant, suggesting that positive selection events play a major role in the peripheral γδ repertoire. Variations in the levels of Vγ2+ cells and Vδ4+ cells was not associated with Mls or MHC haplotype. Analysis of recombinant inbred strains revealed that high Vδ4 expression mapped to the TCR-γ locus, while high Vγ2 expression was influenced by the TCR-δ locus. Backcross analysis confirmed that the TCR loci dominantly influenced the level of Vδ4+ cells and Vγ2+ cells; however, there was clear evidence that multiple genes affect the TCR-γδ repertoire.