There have been rather few studies on the comparative efficacy of the ClosureFAST endovenous radiofrequency obliteration (RFO) technique and endovasal laser obliteration (EVLO) at a near-1500 nm wavelength for the treatment of primary varicosis. The present work was designed to elucidate the major differences between the two methods. The multicenter prospective non-randomized study included the patients with varicose lesions in the basin of the great saphenous vein (GSV). The size of the sample was calculated based on the results of a pilot study. The main criterion for the efficacy of therapy was pain intensity on day 1 after surgery estimated from the numerical rating scale. The additional criteria were the frequency of ablation/obliteration/recanalization, the dynamics of the quality of life (CIVIQ-2 questionnaire), and severity of the disease (assessed based on the VCSS scale 1 year after the treatment). The data obtained were analysed by non-parametric methods. The Mann-Whitney test was applied for the analysis of differences between the groups and the Wilcoxon test for the intragroup analysis. The frequency of outcomes was estimated using Pearson's chi-square test. In addition, the relative risk of recanalization between the groups was calculated. A total of 192 patients underwent 84 EVLO procedures at a wavelength of 1470 nm (with the use of end-emitting fibers) and 108 ClosureFAST RFO procedures. Median of pain intensity in the femoral segment on day 1 after RFO (Me=1) was significantly lower than after EVLO (Me=3), p=0.00001. The frequency of ablation was higher in the EVLO group (p=0.05). The differences in the frequency of recanalizaion and obliteration were insignificant (p=0.53 and p=0.07 respectively). The relative risk of recanalization was estimated at 1.02 95% CI (0.96-1.08). The improvement in the quality of life and the reduction in the severity of the disease (evaluated from the CIVIQ-2 questionnaire and the VCSS scale respectively 1 year after RFO and EVLO were statistically significant (p<0.000001 in all the cases). These changes were more pronounced in the patients undergoing RFO than after EVLO (p=0.0002 and p=0.00001 respectively). It is concluded that ClosureFAST RFO is associated with less severe pain syndrome than EVLO performed at 1470 nm with the use of the emitting fibers. However, the frequency of GSV obliteration and recanalization within 1 year after the treatment was not significantly different between the two methods. ClosureFAST RFO resulted in more pronounced positive dynamics in the quality of life and severity of the disease compared with 1470 nm EVLO. Nevertheless, the clinical significance of this difference is negligible.