Objectives: To assess the efficacy of the ClariVein® system of mechanico-chemical ablation of superficial vein incompetence. Method: ClariVein® treatment uses a micropuncture technique and a 4-Fr sheath to allow a catheter to be placed 1.5 cm from the saphenofemoral junction. Unlike laser (endovenous laser treatment (EVLT)) or radiofrequency ablation (RFA), no tumescence is required. The technique depends on a wire rotating at 3500 r/min causing endothelial damage whilst liquid sclerosant (1.5% sodium tetradecyl sulphate) is infused. The wire is pulled back whilst continuously infusing sclerosant along the target vessel’s length. Initially, 8 mL of dilute sclerosant was used, but this was subsequently increased to 12 mL. No routine post-op analgesia was prescribed and specifically no non-steroidal anti-inflammatory drugs. Procedure times and pain scores (visual analogue scale) were recorded and compared to EVLT and RFA. All patients were invited for duplex post-procedure. Results: Fifty-one great saphenous veins and six short saphenous veins were treated and followed up with duplex in the 10 months from July 2011. No major complications or deep vein thrombosis were reported. Duplex showed patency of three treated veins with two more veins having only a short length of occlusion, giving a technical success rate of 91%. Comparison with 50 RFA and 40 EVLT showed procedure times were significantly less for ClariVein® (23.0±8.3 min) than for either RFA (37.9±8.3 min) or EVLT (44.1±11.4 min). Median pain scores were significantly lower for ClariVein® than RFA and EVLT (1 vs. 5 vs. 6, p<0.01). Conclusion: Mechanochemical ablation with the ClariVein® system is safe and effective. After some initial failures, the use of 12 mL of dilute sclerosant results in a very high technical success rate >90% which accords with the limited published literature. Procedure times and pain scores are significantly better than for RFA and EVLT. We await the longterm clinical outcomes.