We report two cases of radiofrequency catheter ablation (RFCA) with atrioventricular nodal reentrant tachycardia (AVNRT) in patients associated with persistent left superior vena cava (PLSVC). AVNRT with PLSVC differs in terms of catheter positioning and location of slow AV nodal pathway as compared with AVNRT alone. In our two patients, a coronary sinus electrode catheter was easily introduced through the PLSVC and directly into the coronary sinus. Successful RFCA was performed with the energy delivery at the bed of the proximal portion of the markedly enlarged coronary sinus without any complications in the two patients.