BACKGROUND: Ablation of atrial fibrillation is generally considered safe and effective. However, atrial-esophageal fistulas have recently been reported as a rare but fatal complication. OBJECTIVE: To describe 9 patients with atrial-esophageal fistulas after ablation for atrial fibrillation. DESIGN: Retrospective case series. SETTING: Institutions where cardiologists performed atrial fibrillation ablation procedures. PATIENTS: 9 patients with atrial-esophageal fistulas after atrial fibrillation ablation. MEASUREMENTS: Demographic characteristics, mortality, presenting signs and symptoms, and days to presentation. RESULTS: Patients presented a mean of 12.3 days (range, 10 to 16 days) after their procedures. Nonspecific symptoms included fever, leukocytosis, and neurologic abnormalities. All patients died. Only 4 patients received correct diagnoses before death, although all patients presented to a physician. In 3 patients, surgical repair was attempted. LIMITATIONS: Few physicians reported cases, and only approximate numbers of procedures performed by the physicians are known. Thus, the authors could not estimate the incidence of atrial-esophageal fistulas after ablation. CONCLUSIONS: Formation of atrial-esophageal fistulas is a rare but potentially devastating complication of atrial fibrillation ablation. This disorder may have an indolent presentation and may mimic other disease states, such as stroke or sepsis.