Ulcerative lichen planus of the sole is an unusual variant of lichen planus, with only a few reported cases in the literature. The present authors present the case of a 77-year-old woman with relapsing erosive lichen planus of the feet with large, ill-defined and painful ulcers of the soles, which were present for 24 months and made her walking almost impossible. Ulcerative lichen planus is remarkably known as unresponsive to usual local and systemic therapies, and the cutaneous plantar lesions are even more difficult to treat. In our patient, we achieved very good results with topically applied tacrolimus ointment 0.1%, twice a day. The pain disappeared at the end of the first week of treatment, and after 4 weeks, the ulcerations were 95% epithelized, and the patient was able to walk without any discomfort. During the treatment, the present authors did not notice any undesirable secondary effects.