Malignant transformation of recurrent respiratory papilloma is rare and is usually associated with a history of radiotherapy or tobacco abuse or both. Recently, we experienced a case of squamous cell carcinoma transformed from recurrent respiratory papilloma in the vallecula. A 59 year old woman visited our ENT OPD on November 16, 1988, because of foreign body sensation of deep neck for several years. On physical examination, we found smooth glistening brownish mass in the vallecula and the epiglottis tip. She smoked 27 years. Initial biopsy from the vallecula revealed squamous cell papilloma. Under the impression of papilloma, was attempted to excise the mass under the suspension laryngoscopy, which turned out to be squamous cell carcinoma. The residual tumor was removed by the supraglottic laryngectomy. We report this case with a review of litertures.