Aim: The rate of liver abscesses after radiofrequency ablation (RFA) of liver tumors is probably high in patients with a biliary tract drainage procedure connecting the biliary duct system to the upper gastrointestinal tract. And yet, to date this rate, the time of onset of these abscesses, and the prior status of the bile ducts have never been reported in the literature.Methods: Among 574 patients treated with RFA over 8 years, only 11 patients (with 13 sessions of RFA, 2 patients undergoing two different RFA sessions) presented with an enterobiliary anastomosis or biliary stenting at the time of RFA. This is a retrospective study of patients who were verified prospectively.Results: Among the 9 patients in whom a biliary tract procedure preceded RFA, 4 developed a liver abscess at the site of RFA, which emerged between 13 and 62 days after RFA. It occurred in spite of different types of short-term antibiotic prophylaxis. Pathogenic bacteria were typical of the digestive flora. Abscesses were cured after percutaneous drainage. No abscess occurred among the 4 patients in whom a biliary tract diversion was performed synchronously with RFA.Conclusion: When RFA is performed in a patient with a preexisting biliary diversion, the risk of developing a liver abscess is high. Currently, we are unable to recommend any kind of preventive antibiotherapy. A preexisting biliary diversion is not an absolute contraindication for RFA, but the risk of developing a liver abscess is close to 40-50%. When RFA is performed synchronously with a biliary diversion, the risk of a liver abscess seems to disappear.