Oral leukoplakia is a precancerous lesion of the oral mucosa. The risk of malignant transformation depends on the clinical and histologic classification and the location of the lesion. For a nonhomogeneous leukoplakia, this risk is 23.4% to 38.0%. In the presence of epithelial dysplasia, the possibility of malignant transformation is 36.3% to 43.0%. Leukoplakia is limited to the epithelium, so a selective removal of this part of the mucosa seems to be the best preventive treatment. Carbon dioxide laser surgery accomplishes a superficial removal by evaporation. A total of 70 patients with 103 oral leukoplakias were treated with carbon dioxide laser evaporation. This resulted in an excellent wound healing with virtually no scarring. The patients were followed up during a period of up to 12 years (mean 5.3 years), showing a cure rate of 90%.