Introduction: Mechanism and result of catheter ablation of atrial tachyarrhythmias after Maze surgery are not reported in Korea. Methods: Consecutive 6 patients (5 women, 47짹15 years) with drug-resistant or drug-intolerant atrial tachyarrhythmias after Maze surgery were included in this study. Mapping and ablation was performed using a non-irrigated tip or externally irrigated tip catheter. Entrainment and activation mapping was used for delineation of reentrant circuit or focal source of atrial tachyarrhythmias and electroanatomic mapping was used in 2 patients. Results: Previous cardiac operation concomitant with Maze surgery was as follows: mitral valve surgery in 3, atrial septal defect closure in 2, surgery for Ebstein���s anomaly in 1 patient. Sinus node dysfunction was present in 2 patients. Eight different atrial flutter/tachycardia (cycle length 282짹50 ms) were induced in these patients. Mechanisms of atrial arrhythmias were reentry around right atrial periatriotomy in 3, left atrial roof-dependent flutter in 2, mitral isthmus-dependent flutter in 1, cavotricuspid isthmus dependent flutter in 1 and focal atrial tachycardia from the coronary sinus os in 1. Of 8 induced tachyarrhythmias 6 atrial flutter/tachycardia were successfully terminated with radiofrequency energy and rendered noninducible. One patient with typical AV node reentry underwent successful slow pathway modification. One patient who had failed ablation underwent pacemaker implantation. Two patients underwent successful ablation for recurrent right atrial atypical flutter after initial procedure. During 7짹6 months follow-period 5 patients remained free of tachyarrhythmia without medication (4 patients) and with medication (in 1 patient). Conclusion: Majority of atrial arrhythmias after Maze surgery were due to macroreentry. Catheter ablation of post-Maze atrial tachyarrhythmias is feasible and has an acceptable short-term result.