Hepatocellular carcinoma (HCC) is one of the most common cancer types worldwide. Percutaneous radiofrequency ablation (RFA) for HCC was introduced in Japan in 1999. It has been established as a major local treatment method worldwide including in Japan. On comparing outcomes between resection and RFA, they were comparable when cases were limited to those with 3 or fewer tumors of size 3 cm or smaller in many reports, based on which RFA has become the main treatment for small HCCs. RFA was introduced into our system at Toho University Medical Center Omori Hospital in 1999, and we treat nearly 200 HCC cases annually with RFA. Although individual medical facilities use their own methods of RFA, we would like to share our experience of RFA treatment protocols.