We have developed an outpatient technique for high-risk varicose patients, using local anesthesia and cryo-sclerosis of the vein wall. A flexible cryo-probe is introduced in the vessel lumen, and its tip refrigerated to --89 degrees C. Thrombosis is thus induced with a limited inflammatory reaction and no pain. The vein then undergoes a progressive fibrosis, and recanalisation was not observed. Clinical results have been excellent on 44 patients who could not be submitted to standard surgical techniques, due to age and obesity.