Chronic venous insufficiency (CVI) is the most common vascular disease and represents a significant health care problem in the United States. Reflux of the great saphenous vein is the most common cause of this condition, whose symptoms include varicose veins, leg swelling, skin discoloration, and ulceration. The traditional treatment of this condition is saphenofemoral ligation with stripping of the saphenous vein followed by varicose vein removal, if necessary. Recent advances in minimally invasive endovenous therapy have led to the development of catheter-based radiofrequency ablation (RFA) of the saphenous vein, which has gained an increasing acceptance in clinical practice. Endovenous RFA was introduced into clinical practice in Europe in 1998 and in the United States in 1999. Since then, over 250,000 procedures have been performed worldwide. Procedure safety and efficacy are well understood, with over 60 publications on the subject in the peer review literature, including four randomized trials comparing this technology with traditional vein stripping surgery. With the advent of tumescent anesthesia, the majority of RFA procedures are now performed in an office setting. This article examines the current technology using RFA in saphenous vein ablation with the Closure catheter system. Procedural techniques and clinical outcome using RFA in saphenous vein ablation are discussed. Clinical data comparing RFA versus saphenous vein stripping are also examined. Lastly, the clinical utility of a new RFA catheter, ClosureFAST, is discussed. ClosureFAST is a new generation of RFA catheter and has exhibited significant improvement in the ease of use and the procedure speed over the previous generation catheters while maintaining the favorable patient recovery profile seen with the RFA technology.