BACKGROUND. A variety of lasers have been used in an attempt to treat leg vein telangiectasia OBJECTIVE. To evaluate the feasibility of a new 940 nm diode laser for the treatment of leg vein telangiectasia. METHODS. Thirty-one patients with leg vein telangiectasia were treated with a diode laser; 26 of these with 940 nm, 300-350 J/cm(2), 40-70 msec, 1.0 mm handpiece, one pass, and 5 of these with 940 nm, 815 J/cm(2), 50 msec, 0.5 mm handpiece, one pass. Each subject had three treatments of the same site at 4-week intervals. Photographs taken before and 4 weeks after the last treatment were evaluated by two independent observers for vessel clearance. RESULTS. In those 26 patients treated with a fluence of 300-350 J/cm(2), a vessel clearance of greater than 50% was achieved in 20 patients (76%), 12 of these patients had clearance rates greater than 75%. A clearance rate of less than 50% was obtained in six patients, with three of these patients showing responses of less than 25%. In five patients treated with a fluence of 815 J/cm(2) a clearance rate of more than 75% was observed. CONCLUSIONS. In this preliminary study a 940 nm diode laser was shown to be safe and effective for the treatment of leg vein telangiectasia.