BACKGROUND: The treatment of vitiligo is still a challenge, but ultraviolet B narrow-band (UVB-NB) therapy has been recently reported to be an effective and safe therapeutic option in patients with vitiligo. OBJECTIVE: The purpose of this study is a critical evaluation of the variants (body sites, age, duration of the disease, and duration of the therapy) influencing the clinical response to UVB-NB therapy. METHODS: Sixty patients (23 male and 37 female), aged 6 to 70 years, with vitiligo, were treated with UVB-NB therapy over a maximum period of 2 years. The evaluation of the percentage of repigmentation was done through photographs. RESULTS: The lesions located on the face obtained a complete repigmentation in 68% of the patients, on the neck in 57.89%, and on the trunk in 50% within the first year of the therapy. In young patients vs. adults patients, the lesions located on the neck obtained a complete repigmentation in 83.33% vs. 46.15%, on the upper limbs in 28.57% vs. 9.52%, and on the lower limbs in 25% vs. 16.67%. In patients with vitiligo of recent onset, the lesions located on the neck obtained a complete repigmentation in 83.33%, on the upper limbs in 33.33%, and on the lower limbs in 28.57%. Hands did not give a positive response in either groups. CONCLUSION: This study shows that certain body sites respond better than others to the UVB-NB therapy; patients, aged less than 20 years, with recent vitiligo, achieve more repigmentation; the duration of the therapy can influence the response of the lesions over hands and lower limbs, showing only mild repigmentation.