Background: Newer technologies such as three-dimensional mapping and echocardiography can decrease x-ray exposure during catheter ablation. Many right-sided tachycardias can now be ablated without fluoroscopy. Left-sided tachycardias, however, have not yet been ablated using a zero fluoroscopy approach. Objective: This study sought to examine the utility of trans-esophageal echocardiography (TEE) in providing adequate imaging as an alternative to fluoroscopy for transseptal puncture. When combined with NavX guidance (St. Jude Medical, St. Paul, MN, USA), fluoroscopy may not be necessary. Methods: Ten pediatric patients with supraventricular tachycardia (SVT) had accessory pathways mapped to the left side. Right atrial and coronary sinus geometries were created using NavX. Once a left-sided pathway was confirmed, a transseptal puncture was performed. A guide wire was placed in the SVC and confirmed by TEE. A transseptal sheath and dilator were advanced over the wire and positioned with TEE guidance so that the tip of the dilator was tenting the fossa ovalis. A transseptal needle was advanced across the fossa. Left atrial location of the needle tip was confirmed on TEE by saline contrast injection. The sheath and dilator were advanced over the needle with continuous pressure monitoring and TEE. Once the sheath was appropriately positioned, the ablation was completed using NavX guidance. Results: All patients had acutely successful ablations and none required the use of fluoroscopy. Number of cryo lesions ranged from five to 19, with a mean of 9. Mean procedure time was 4.4 hours, with a range of 3.2 hours to 7.2 hours. There were no complications. One patient had recurrence. Conclusions: Three-dimensional mapping combined with TEE shows potential for eliminating fluoroscopy use during catheter ablation.