In some patients with rheumatoid synovitis the distribution of V_δ gene families used by freshly isolated T lymphocytes from the synovial fluid and peripheral blood is different: peripheral blood T lymphocytes preferentially use the V_δ2 gene segment, whereas the majority of synovial fluid T lymphocytes use the V_δ1. The antigenic diversity of T cell receptor γ/δ is mainly dependent upon base sequences in the V‐J junction. In the present study we investigated whether the synovial fluid T lymphocytes expressing the V_δ1 gene segment were derived from a polyclonal or monoclonal expansion. The sequences encoding the V‐J junctions of 11 cDNA clones derived from the synovium of two patients with chronic arthritis were determined. Our data demonstrate that the V_δ1 cDNA clones have different V‐J junction sequences. This indicates that the V_δ1‐expressing T cells found in the synovial compartment are polyclonally expanded.