Actinic cheilitis is a premalignant alteration of the lip caused by chronic exposure to solar ultraviolet radiation, and has the potential to evolve into a squamous cell carcinoma. A case of CO₂ laser treatment of actinic cheilitis with squamous cell carcinoma of the lower lip is presented, emphasizing the importance of early detection. The lesion was delimited and the CO₂ laser was used in continuous mode with the following parameters: 0.8 mm focus, 4 W, power density of 512 W/cm², fluency of 0.154 J/cm². The results showed a functional and esthetic result of excellent quality.