Background Transarterial chemoembolization (TACE) is an effective downstaging procedure for hepatocellular carcinoma (HCC). However, knowledge of the effectiveness of radiofrequency ablation (RFA) after downstaging of HCC is currently lacking. Purpose To evaluate the clinical outcomes of RFA after downstaging of HCC by using TACE. Materials and Methods This retrospective study investigated a cohort of patients who underwent RFA with curative intent after downstaging with TACE to meet Milan criteria (one lesion up to 5 cm or no more than three lesions ≤3 cm without vascular invasion or extrahepatic metastasis) from January 2012 to July 2017. A control group of patients initially meeting the Milan criteria also underwent RFA as first-line treatment in the same period. Overall survival (OS), disease-free survival (DFS), and major complication rates were compared by using the log-rank test. To reduce potential bias, a propensity score analysis was also performed. Results There were 72 patients (median age, 56.5 years; range, 30-78 years; 67 men) in the downstaging group and 357 patients meeting the Milan criteria (median age, 58.0 years; range, 25-87 years; 313 men) included in this study. After propensity score matching, the 1-, 3-, and 5-year OS rates were 99%, 80%, and 66%, respectively, for the patients in the downstaging group and 94%, 84%, and 69%, respectively, for the patients in the Milan criteria group. The 1-, 3-, and 5-year DFS rate were 73%, 34%, and 24% for the downstaging group and 74%, 43%, and 37% for the Milan criteria group. There were no differences in the OS, DFS, or major complication rates between the two groups (P = .74, P = .39, P = .73, respectively). Conclusion The long-term patient survival and major complication rates of radiofrequency ablation following transarterial chemoembolization downstaging for hepatocellular carcinoma were similar to that of patients initially meeting the Milan criteria. © RSNA, 2019 See also the editorial by vanSonnenberg and Mueller in this issue.