Background: Radiofrequency (RF) power is capable of ablation of neoplastic tissue arising from Barrett's esophagus. Endoscopic catheter bipolar RF ablation is a new technique for ablation of neoplastic tissue in the bile duct. Objective: To determine the effect of RF power on bile duct and solid organ histology. Design: Nonsurvival animal study. Setting: Academic center. Patients: This study involved 4 Yorkshire farm swine. Intervention: After we made a midline laparotomy incision, a bipolar RF catheter was placed with 3 power (5, 7, 10 W) and voltage settings (66, 132, 190 V) in the bile duct and solid organs (liver, spleen, kidney, and pancreas). Gross and histologic examinations were performed. Main Outcome Measurements: Depth of ablation in the bile duct wall, characteristics of the ablation in the solid organs. Results: An endoscopic bipolar RF catheter produced incomplete (bile duct), patchy ablation (pancreas) with 5 watts, intramural (bile duct) or confluent ablation with 7 watts, and transmural (bile duct) ablation at 10 W. The depth of ablation in the bile duct was 0.9 ± 0.3, 1.5 ± 0.2, 2.3 ± 0.6 mm at 5, 7, and 10 W, respectively (analysis of variance; P =.02). Histologic ablation was not achieved in the liver, although gross changes were seen. Limitations: Animal study, normal bile duct. Conclusion: RF energy applied to the bile duct or solid organs resulted in controlled ablation with a linear relationship between the depth of ablation in the bile duct and RF power.