Our objective was to chronicle our experience in using sclerosant foam to treat severe chronic venous insufficiency (CVI). Forty-four patients with 60 limbs severely affected by severe CVI were entered into the study. They had lipodermatosclerosis, CEAP 4 (seven limbs); atrophie blanche or scars of healed venous ulcerations, CEAP 5 (18 limbs); and frank, open venous ulcers, CEAP 6 (35 limbs). Patients and limbs were collected into three groups. In group I, all limbs were treated with compression without intervention. Group II consisted of crossover patients who failed compression treatment. Group III consisted of patients treated promptly with sclerosant foam therapy without a waiting period of compression. A standing Doppler duplex reflux examination was done in all cases. Compression was by Unna boot or long stretch elastic bandaging. Foam was generated from Polidocanol 1%, 2%, or 3% by the two-syringe technique and administered under ultrasound guidance. Posttreatment compression was used for 14 days. In addition to clinical and ultrasound evaluation at 2, 7, 14, and 30 days, venous severity scoring was noted at entry and discharge. In group I, 12 patients were discharged from care within 6 weeks of initiating compression. All eight of the class 6 limbs had healed. Group II consisted of four CEAP class 5 limbs and eight class 6 limbs that had failed to heal with compression. Five of eight venous ulcers healed within 2 weeks, two more healed by 4 weeks, and one required 6 weeks to heal. In group III, 7 of 11 venous ulcers healed within 2 weeks and four more within 4 weeks. Venous severity scores reflected the success of treatment, with the greatest change occurring in group III and the least in group I. Limbs treated with foam had a statistically better outcome than those without (p = 0.041). One patient failed foam sclerotherapy, another had pulmonary emboli 4 months after foam treatment, and a single medial gastrocnemius thrombus was discovered 24 hr after treatment. Treatment of severe CVI with compression and foam sclerotherapy causes more rapid resolution of the venous insufficiency complications and does so without an increase in morbidity.