The purpose of this study was to compare the efficacy of retinoic acid in an oral base 0.05% with fluocinolone acetonide in an oral base 0.1% in the treatment of atrophic and erosive oral lichen planus. Thirty-three patients with histologically proven oral lichen planus were asked to participate in the study. Lesions were scored ranging from 0 (no lesion) to 5 (large erosion) according to the severity. Patients were randomly assigned to receive either topical fluocinolone acetonide or topical retinoic acid. They were instructed to apply the medication on dried lesions four times a day. The lesions were evaluated after 2 and 4 weeks of treatment. The sign scores were analyzed by the Wilcoxon rank sum test. Eighteen patients receiving topical fluocinolone acetonide improved from the average score of 3.0 to 1.5 after 4 weeks of treatment, whereas 15 patients receiving topical retinoic acid showed little change (average score, 2.9 and 2.4, respectively). The changes were statistically significantly different between the two groups (p = 0.01). The results suggest that 0.1% fluocinolone acetonide reduced the severity of atrophic and erosive oral lichen planus better than 0.05% retinoic acid.