Radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC) is a promising method for controlling tumors, although it does not entirely eliminate recurrence. Oxidative stress is associated with the progression of hepatocarcinogenesis, while also acting as an anticancer response. The objective of the present study was to investigate the factors influencing post-RFA outcomes. We recruited 235 newly diagnosed HCC patients who received RFA for single tumors. The patients with recurrence were sub-grouped into early and segmental recurrence groups. The characteristics of the sub-grouped patients were evaluated, including by measuring oxidative stress marker reactive oxygen metabolites and antioxidant marker OXY-adsorbent tests. The factors associated with poor survival were a high Child-Pugh score and early recurrence within 2 years in the same segment. The patients who experienced recurrence within 2 years in the same segment showed a larger tumor diameter than did others. According to a multivariate analysis, the OXY values were also significantly low in these patients. In conclusion, maintaining the antioxidant reservoir function with a high OXY value might be necessary to prevent early recurrence within the RFA-treated segment.