The present study was aimed at evaluating correlations between clinical response and the histochemical and immunohistochemical changes in vitiligo patches treated with narrow-band UVB phototherapy. Eighteen patients, 13 females and 5 males, aged between 15 and 67 years, affected by vitiligo were recruited and 14 patients completed the study. Before starting the narrow-band UVB treatment three biopsies were carried out on the lesional, perilesional and healthy skin of each patient, excluding the face. After 9 months treatment an additional biopsy was performed on repigmented skin areas adjacent to the lesional biopsy site. For the histochemical evaluation, the Masson-Fontana argentaffin reaction was carried out; for the immunohistochemical study, two antigens were studied: tyrosinase and HMB 45. Clinical improvement was assessed by evaluating the repigmented surfaces, expressed in percentages of the respective vitiligo areas. The results obtained confirm the effectiveness and safety of narrow-band UVB phototherapy for vitiligo, in terms of both good clinical-histological results and absence of important side effects. In addition to attesting the efficacy of narrow-band UVB phototherapy, immunohistochemical tests also appeared to have a potential interest for prognostic purposes.