Aim — the objective of the present study was to analyze the results of endovenous laser ablation (EVLA) of the great saphenous veins (GSV) more than 2 cm diameter. Material and methods. This prospective non-comparative study included 112 patients who had been operated on during the period from November 2014 till December 2016. We performed a total of 124 EVLA procedures. The diameter of the veins close to the sapheno-femoral junction ranged from 21 to 43 mm (mean 28±4,3 mm).We used the 1470 nm laser, radial fibers and the special pull-back device. All veins were treated under tumescent anesthesia. In all cases, we used the power of 8—10 W. The linear energy density in the dilated segments varied from 101.3 to 172 J/cm. The length of the observation period was from 160 to 440 days (mean 298). Results. The next day after EVLA, 106 (85.5%) veins were found to be occluded. In 18 (14.5%) cases, the residual lumen could be seen in the dilated segments, but it closed in 15 (12.1%) patients within the next 7 days. In three (2.4%) cases, we re-treated the patients by EVLA during the early postoperative period with the perfect technical result. Recanalization with the pathological reflux was documented only in 1 (0.8%) case. This patient was treated by ultrasound-guided foam-form sclerotherapy (UGST), also with the good technical result. Conclusion. EVLA with the use of the 1470 nm laser and the radial fibers provides an efficient tool for the treatment of the large caliber veins more than 2 cm in diameter. We have reached the occlusion of GSV in 97.6% of the cases in the early follow-up period. The intervention had to be repeated in 2.4% of the cases. The occlusion rate during the long-term follow-up period amounted to 99,2%.