Background/aim: Great saphenous vein (GSV) incompetence is the most common cause of superficial venous insufficiency. Endovenous laser ablation (EVLA) and radiofrequency ablation (RFA) are both associated with excellent technical, clinical and patient-reported outcomes for the treatment of varicose veins. The aim of this study is to compare the efficacy, symptomatic outcome and postoperative complications of endovenous thermal ablation using the radiofrequency ablation (VenefitCovidienClosureFast™ Endovenous Radiofrequency Ablation Catheter) and laser (Nd: YAG laser 1320 nm CoolTouch™, Roseville, California) ablation techniques of the great saphenous vein (GSV). Patients and methods: A total of 123 limbs in 110 patients. In the laser group there was 45 patients with unilateral procedure and 8 patients with bilateral procedures. In the RF group there was 52 patient with unilateral procedure and 5 patients with bilateral procedures. In patients who required bilateral treatment, procedures were performed on different sessions with a time interval of at least 1 month. In the statistical analysis the differences between the study groups were compared by Chi square (χ2) test for categorical variables, and student's T test for continuous variables. Values of P < 0.05 were considered significant. Results: The study enrolled 110 patients (123 limbs): 53 (48%) were randomized to EVLA and 57 (52%) to RFA, and 13 (12%) had bilateral GSV incompetence. At 1 week, one patient in the RFA group had an open GSV and was deemed a failure. Venous duplex examination was done in the post-procedural visits at one week, one month, and 6 months to verify objectively GSV closure as evidenced by absence of GSV flow and recanalization. This duplex follow-up showed complete GSV closure throughout the treated segments in all patients in both groups at all follow-up visits. There was no difference between the 2 groups regarding effectiveness of the procedure. Regarding the post-procedural adverse events there was no recorded cases of deep vein thrombosis (DVT) or paresthesia in both groups. There was a nearly significant difference regarding bruises along the course of the treated GSV, as well as inactivity as measured by the visual analogue scale (VAS) in favor of the laser group noticed at 1-week follow up. Conclusion: Radiofrequency using VenefitCovidienClosureFast™ ablation was associated with less postoperative pain, tenderness, ecchymosis and better postoperative recovery and QOL parameters than endovenous laser for thermal ablation of the GSV. However, clinical and quality-of-life improvements were similar at 1 month for the two treatment modalities.