Background and Objectives : Intraatrial reentrant tachycardia (IART) is one of the most troublesome tachycardia, especially in postsurgical patients with congenital heart disease, due to high recurrence rat. The aim of this study is to evaluate the clinical and electrophysiological characteristics of IART. Materials and Methods : Fifteen tachycardia circuits in 10 consecutive patients (Mean age 52짹9, female 4) with IART were mapped and ablated conventionally. Six patients had corrected congenital heart disease (4 Atrial septal defect, 1 Ventricular septal defect, 1 Tetralogy of Fallot) and 2 for acquired heart disease, but structurally normal hearts in 2 patients. Isthmus dependent atrial flutter was the most common arrhythmia at initial presentation ( 6 patients, 60%) and 4 were presented in the form of atrial tachycardia (AT). Results : Acute success rate was 100%. Among 6 patients with atrial flutter, tachycardia recurred in 3 (50%) in the form of AT after 5짹3 months of follow up. AT with different P wave morphology recurred in 2 patients with previously successful AT patients. The cycle length of all the tachycardia was 269짹36 ms. Tachycardia circuits and conduction barriers could be found at the right atrial free wall in all AT. Non-contact 3 dimensional mapping system (Ensite 3000) was used in 4 patients for redo procedure. All were free of arrhythmias during the follow-up period of 10짹9 months. Conclusion : Scar-related IART can be observed in structurally normal heart. Initial use of 3 dimensional mapping system is reasonable in terms of both patient���s convenience and cost-effectiveness.