The role of dendritic cells in vitiligo is still unclear. Few studies have provided contradictory results about their quantitative variation and no data exist concerning their immunophenotypical distribution in diseased skin. The purpose of our study was to analyze the presence, the distribution, the immunophenotypical markers and the effects of nb-UVB therapy on dendritic cells in non-lesional, perilesional, and lesional vitiligo skin. Punch-biopsies of 6 mm were taken from lesional, perilesional, and non-lesional skin of 12 patients affected by non-segmental vitiligo, treated with nb-UVB. An immunohistochemical and an ultrastructural analysis were performed. Immunohistochemical and ultrastructural analysis showed both quantitative and qualitative modifications of Langerhans cells. Nb-UVB therapy, one of the most effective treatments for the disease, was able to reduce the Langerhans cells number and to redistribute main dendritic subsets. This study underlines the importance of dendritic cells, Langerhans cells in particular, in non-segmental vitiligo, in its pathogenesis and in its better therapeutical approach.