Catheter guided ablation of cardiac arrhythmias is an effective and safe procedure for the treatment of most supraventricular and selected ventricular tachycardias. Because catheter manipulation is fluoroscopically guided, there is risk of radiation induced injury, especially during prolonged procedures. The Food and Drug Administration has recently issued a bulletin warning of the risks of acute skin injury occurring during fluoroscopically guided procedures that result in an exposure level exceeding 2 Gray units (Gy). This study was performed as an investigation into the risk of radiation induced skin injury during arrhythmia ablation procedures. The amount of radiation exposure for 500 patients who underwent ablation was calculated based upon fluoroscopy times and the entrance dose of radiation (0.02 Gy/min). The mean radiation exposure was 0.93 +/- 0.62 Gy. Although 5.6% of patients (n = 28) received enough radiation exposure to reach the threshold dose (2 Gy) for early transient erythema, no clinical manifestations of acute radiation induced skin injury were observed. No patients achieved the threshold dose for irreversible skin injury. Patients undergoing AV node ablation or modification received significantly less radiation (0.39 +/- 0.40 Gy and 0.79 +/- 0.44 Gy, respectively) than patients undergoing other ablation procedures (0.94-1.45 Gy, P < 0.05). There was no association between the magnitude of radiation exposure and the presence of underlying heart disease. Patients undergoing ablation of accessory pathways were exposed to more radiation if there was a right-sided pathway (1.69 +/- 0.93 Gy) compared to other sites (0.87-1.24 Gy, P < 0.05). This study demonstrates that the risk of significant radiation induced skin injury during arrhythmia ablation procedures is low provided that precautions are taken to minimize radiation exposure.