Discoid lupus erythematosus (DLE) is a chronic connective tissue disease of unknown etiology, but immunologic factors may play an important role in the pathogenesis. We investigated the features of immunohistochemical characterization of the cellular infiltrate in DLE. Skin samples were obtained from 5 patients using a 6 mm punch biopsy. Samples were stained with monoclonal antibodies against CD1a, CD3, CD4, CD8, CD20, CD25, CD30, and CD57. The number of cells stained with each monoclonal antibody was calculated. The number of cells stained with each monoclonal antibody in the dermis infiltration in DLE was calculated and all were higher than those in the normal control. The numbers of CD3(+), CD4(+), CD8(+), CD20(+), CD25(+), or CD57(+) cells in DLE were statistically higher than those in normal skin (p < 0.05). The numbers of CD1a(+) and CD30(+) cells in DLE were appreciably increased but had no statistical significance compared with normal skin. In conclusion, this study revealed that T lymphocytes, B lymphocytes, and natural killer cells may play some roles in the pathogenesis of DLE.