The risk of relapse after successful repigmentation in vitiligo is estimated to 40% within the first year. It has been shown in atopic dermatitis that continuous low-level use of topical corticosteroids and calcineurin inhibitors in previously affected skin can prevent new flares. We hypothesized that a twice-weekly application of 0.1% tacrolimus ointment might be effective for maintaining repigmentation in therapeutically repigmented lesions of vitiligo patients. After randomization, sixteen patients with 31 patches were assigned to the placebo group and 19 patients with 41 patches were assigned to the tacrolimus group. In the intention-to-treat analysis, 48.4% of lesions showed depigmentation in the placebo group, whereas 26.8% did in the tacrolimus group (P=0.059). The intention-to-treat results did not remain significant after adjustment for within-patient clustering, odds ratio (OR) 2.55; 95% confidence interval (CI; 0.65-9.97); P=0.1765. The per-protocol analysis (n=56) showed that 40% of lesions had some depigmentation in the placebo group, whereas only 9.7% did in the tacrolimus group (P=0.0075). The per-protocol results remained significant after adjustment for within-patient clustering: OR 6.22; 95% CI (1.48-26.12); P=0.0299. Our study shows that twice-weekly application of 0.1% tacrolimus ointment is effective in preventing the depigmentation of vitiligo patches that have been previously successfully repigmented.