We have presented a case of malignant transformation of oral lichen planus along with a review of the literature and a brief description of the disease. We have attempted to indicate that within defined terms, oral lichen planus should be considered a pre-malignant lesion in which incidence of transformation approaches that of clinical oral leukoplakia, yet is clearly distinctive from that disease with regard to age and sex distribution. The erosive form of oral lichen planus most often precedes carcinomatous change. A protocol is described for documentation and periodic follow-up procedures for such patients to possibly intercept a developing malignancy.