This study evaluated the clinical applications, treatment effects, and complications of percutaneous ultrasound (US)-guided radiofrequency ablation (RFA) of intrahepatic cholangiocarcinoma. Ten patients (6 men and 4 women) with histologically proven cholangiocarcinoma underwent US-guided percutaneous RFA. Tumor diameters ranged from 1.9 to 6.8 cm. There were 12 sessions of RFA for 10 solitary cholangiocarcinomas. Eight patients were treated at a single session and two patients had two treatment sessions. The efficacy of RFA was evaluated using contrast-enhanced dynamic computed tomography 1 month after treatment and then every 3 months. Complete necrosis was defined as lack of contrast enhancement of the treated region. There was complete necrosis in eight tumors. In two patients with large tumors (4.7 and 6.8 cm in diameter), enhancement of residual tissue was observed after RFA treatment, indicating residual tumor. Complete necrosis was seen in all five tumors (100%) with diameters of 3.0 cm or less, two of three tumors (67%) with diameters of 3.1-5.0 cm, and one of two tumors (50%) with diameters of more than 5.0 cm. A large biloma was found in one patient after treatment. No serious complications occurred in the other nine patients. In conclusion, percutaneous RFA is effective and successful in the treatment of intrahepatic cholangiocarcinoma of 3 cm or less and satisfactory for tumors of 3-5 cm. The rate of serious complications after RFA is low. Further follow-up is necessary to determine long-term efficacy.