In the murine epidermis, there exist Thy-1+ dendritic epidermal cells (Thy-1+DEC). These cells are Thy-1+, CD45+, CD3+ and asialo GM1+ but CD5-, CD4-, CD8-, or Ia-1-, and express T cell receptor (TCR) gamma delta. Recently, most of these TCR gamma delta of Thy-1 DEC are shown to consist of a V gamma 3-V delta 1 combination. There has been no evidence that the same type of cell population exists in other species except mice. In this study, we investigated the existence of a Thy-1+DEC equivalent in the rat epidermis. The epidermal sheets obtained from rats were stained with various monoclonal antibodies to rat lymphocytes. We developed a monoclonal antibody (1F4) to rat CD3 complex. 1F4 stained thymocytes and peripheral T cells and also immunoprecipitated T cell receptor with CD3 complex. Using 1F4 and a recently developed monoclonal antibody to rat TCR alpha beta, we could identify dendritic CD4-, CD8-, CD5-, CD3+, TCR alpha beta- cells in the rat epidermis. These CD3+, TCR alpha beta- cells are strong candidates as an equivalent to TCR gamma delta + murine Thy-1+ DEC.