BACKGROUND Ablation of ventricular tachycardia and premature ventricular contraction arising at the aortic root has been described. The use of radiofrequency ablation energy has been associated with life-threatening collateral damage. The use of cryoablation as a safer alternative energy source at the aortic root has not been previously described. OBJECTIVE To demonstrate that cautious cryoablation near the ostia of the left main coronary artery is technically feasible and is a safe, effective alternative energy source for ablation at the aortic root. METHODS Six patients (mean age 36 years; 4 women) with refractory frequent premature ventricular contractions or ventricular tachycardia underwent electrophysiological study and ablation. Two patients had associated nonischemic cardiomyopathy. Patients' ventricular arrhythmias were localized by using 3D mapping, with arrhythmia foci being mapped to the left aortic cusp near the left main coronary artery. The proximity to the ostium of the left main coronary artery was confirmed by using intracardiac ultrasound and coronary angiogram. Focal ablation, up to 240 seconds with freeze-thaw-freeze cycles, was performed by using an 8-mm cryoablation catheter via a retrograde aortic approach. RESULTS Termination of ventricular arrhythmia during ablation was observed in all 6 patients. All patients were followed for greater than 6-month postablation. One patient had acute ST-segment elevation during ablation below the left main ostium that resolved within 30 seconds of termination of ablation. There were no postprocedure complications and no significant arrhythmia recurrences. CONCLUSIONS Aortic root ventricular arrhythmia ablation carries an increased risk for collateral damages. This case series demonstrates that cautious cryoablation near the ostia of the left main coronary artery can be performed and is a safe, effective alternative energy source for ablation at the aortic root.