SEVERAL observations suggest interactions between the immune and nervous systems^1,2. Psoriasis and atopic dermatitis may worsen with anxiety and have been associated with anomalous neuropeptide regulation². Neurotransmitters affect lymphocyte function^1–4 and lymphoid organs are innervated^5–9. Calcitonin gene-related peptide (CGRP) is a neuropeptide and vasodilator¹⁰ that modulates some macrophage functions, including antigen presentation in vitro¹¹. CGRP is associated with Langerhans cells (LC) in oesophageal mucosa, particularly during inflammation¹², is present in epidermal nerves and is associated with Merkel cells^10,13–15. We examined the ability of CGRP to modulate LC antigen-presenting function¹⁶ and asked if CGRP-containing nerves impinge on LC. We report here that CGRP-containing nerve fibres are intimately associated with LC in human epidermis and CGRP is found at the surface of some LC. In three functional assays CGRP inhibited LC antigen presentation. These findings indicate that CGRP may have immunomodulatory effects in vivo and suggest a locus of interaction between the nervous system and immunological function.