Cutaneous lymphocyte-associated antigen (CLA) defined by monoclonal antibody (MoAb) HECA-452 has been shown to be preferentially expressed on cutaneous T cells. The CLA expression has been regarded as a homing molecule of T cells to the skin in various inflammatory cutaneous disorders. In this paper we investigated the significance of CLA expression on Langerhans cells (LC) and found that, in normal skin, some epidermal LC express CLA, and that most dermal CD1a positive cells express CLA. When normal skin was organ cultured, the percentage of CLA positive cells in LC and dermal CD1a positive cells decreased appreciably. In diseased skin, epidermal LC increased in number and most LC expressed CLA. Thus, this study suggests that the CLA expression on LC may play as a homing molecule of LC to the skin.