The carbon dioxide laser was used for the treatment of 20 lesions of the oral mucosa in 14 patients. These lesions ranged histologically from benign hyperkeratosis to verrucous carcinoma. The patients selected for this treatment were identified at high risk to develop malignant lesions in the oral cavity. Precise vaporization of the affected mucosa were carried out using the Cavitron 40-300-A CO2 Surgical Laser. Destruction of the surface epithelium and submucosa was achieved by using defocused beam at a setting of 10W. Biopsies were taken at 1 cm intervals at the time of laser treatment. Fourteen of the 20 procedures were carried out under local anesthesia on an outpatient basis. Seven procedures were performed under general anesthesia and 2 patients required 24 h postoperative observation. Local control was achieved in 17 of the 20 treated sites. Two of the three treatment failures occurred in patients in whom the final histology revealed either in situ or invasive squamous carcinoma. Only one patient with dysplasia was not controlled after vaporization of the lesion by the carbon dioxide laser. The laser continues to show encouraging results as an alternative to surgical resection of precancerous mucosal lesions of the oral cavity. Vaporization of the dysplastic lesion(s) with carbon dioxide laser is recommended for patients with an identifiable risk for the development of intraoral malignancy. This is an effective, nonmorbid, inexpensive, quick, and relatively painless method of managing this condition.