In the past decade, both the range of indications and the efficacy and safety of interventional electrophysiology has improved considerably. This progress is attributed to both the accumulating experience of electrophysiologists and the advances in technological tools facilitating the diagnosis and treatment of cardiac arrhythmias. Real-time 3-dimensional transesophageal echocardiography (RT 3D TEE) has emerged as a new imaging tool in the clinical arena. Its ability to image in "real time" cardiac structures "en face" and the almost entire length of intracardiac catheters has made this technique a promising imaging tool to guide percutaneous catheter-based procedures. More recently it has been used in monitoring ablation procedures. In this review, the advantages and current limitations of RT 3D TEE during ablation of cavotricuspid isthmus-dependent atrial flutter and pulmonary vein isolation are described.