Purpose: The purpose of this study was to determine the occlusion rate of incompetent great saphenous veins (GSVs) and small saphenous veins (SSVs) treated with radiofrequency ablation (RFA) and individualize variables associated with recanalization. Materials and methods: A retrospective review of 311 veins (256 GSVs and 55 SSVs) in 211 patients [177 women, 34 men; mean age, 45 years±12 (SD) (range: 18-75 years)] with incompetent GSVs and/or SSVs who were treated using new-generation RFA catheters was performed. The clinical results, occlusion rates, and variables associated with recanalization for the incompetent GSVs and SSVs were analyzed. Results: No major complications were observed in the study population. Ten months after RFA, the occlusion rate was 89% (227/256) for GSVs and 91% (50/55) for SSVs. An increased pre-procedure diameter of the incompetent GSVs was associated with a higher rate of recanalization (OR: 0.825; 95% CI: 0.715-0.952) (P<0.05). No significant differences in age, gender, and side of treated veins were found between patients with recanalization of treated veins and those without recanalization. Conclusion: Our results show that pre-procedure diameter of the GSV is the single risk factor for recanalization after RFA.