We report about a patient with congenitally corrected transposition of the great arteries and ebsteinoid malformation of left atrioventricular (AV) valve who presented with incessant orthodromic atrioventricular reciprocating tachycardia due to a left posteroseptal accessory pathway. Radiofrequency catheter ablation using trans-septal approach successfully eliminated the posteroseptal pathway across the morphologic tricuspid valve. This report highlights the importance of delineating the anatomy of the interatrial septum in complex congenital heart diseases for performing safe trans-septal puncture during ablation of accessory pathways.