During a period of 12 months, 139 patients with 164 intraoral pathologic lesions were treated with a CO2 laser. Intra- and postoperative complications and the method of pain control during and after surgery were recorded. The diagnostic evaluability of the 133 soft tissue biopsy specimens sent for histopathologic analysis was examined, and the clinical and histopathologic diagnoses were compared. Nine intra- and six postoperative complications occurred. Pain control during CO2 laser surgery could be performed with a topical anesthetic in almost one third of the lesions; in the other 111 lesions, a local anesthetic had to be applied. For pain relief after the operation, 101 patients (72.7%) used only an adhesive wound paste, without any additional oral analgesic. The thermal damage from the CO2 laser on the borders of the biopsy specimens never interfered with the pathologist's establishment of a firm diagnosis. The CO2 laser is an appropriate instrument for excisional biopsies of oral soft tissue lesions. Intra- and postoperative complications were minimal, pain relief during and after surgery could be achieved in many cases through topical anesthetics, and incisional or excisional biospsies caused no diagnostic problems because of collateral thermal damage of the specimen from the laser.