Since verrucous carcinoma was first identified as a distinct clinicopathologic entity, a great deal of confusion has developed in interpreting the proper criteria for diagnosis. Various authors, therefore, have developed considerably different concepts of the features that make this lesion a unique variant of squamous cell carcinoma. Consequently, there is great confusion in the literature as to the appropriate therapeutic approach, the incidence of recurrence, and the frequency of anaplastic transformation of verrucous carcinoma. The literature was reviewed to identify all cases of verrucous carcinoma of the oral cavity that appear to meet the clinical and histopathologic criteria for this lesion as originally set forth by Ackerman. The problems encountered in arriving at the diagnosis of verrucous carcinoma are discussed. Cases with at least a 1-year reported follow-up were grouped according to the primary modality of therapy employed and were evaluated as to the effectiveness of the initial therapy. The frequency of anaplastic transformation following radiation therapy is also addressed.