Purpose: The purpose of this study is to retrospectively evaluate the outcomes of radiofrequency ablation (RFA) of low-risk small papillary thyroid carcinomas (PTCs) in patients who were ineligible for surgery.Materials and methods: Between 2005 and 2009, six PTCs (mean diameter, 0.92cm; range, 0.6-1.3cm) in six patients were treated with RFA by three radiologists in two hospitals. The inclusion criteria for this study were (1) pathologically confirmed PTC without cytological aggressiveness, (2) single PTC without extrathyroidal extension, (3) no metastatic tumours and (4) ineligibility for surgery. RFA was performed using a radiofrequency generator and an 18-gauge internally cooled electrode. The medical records were reviewed and analysed, focussing on the procedural profiles of RFA, symptoms and complications during and after RFA, and changes in tumours on follow-up ultrasonography.Results: Before and after RFA, the results of thyroid function tests were normal in all patients. During 48.512.3 months (range, 36-65 months) of follow-up, along with a significant reduction in the mean volume (98.5 +/- 3.3%), four ablation zones (4/6, 66.7%) completely disappeared. Two ablation zones exhibited only small calcified residues with nearly complete disappearance of the corresponding non-calcified solid portions, and in one of them, malignant cells were absent as assessed by fine-needle aspiration and core-needle biopsy. Transient hypertension with mild headache (n=1) and mild neck pain (n=1) developed during the procedure and subsided without any treatment.Conclusion: Besides surgery and active surveillance, which are conflicting currently used management plans, RFA might represent an effective and a safe alternative for managing low-risk small PTCs, especially in patients ineligible for surgery.