Wolff-Parkinson-White (WPW) syndrome can develop paroxysmal supraventricular tachycardia (PSVT) or/and paroxysmal atrial fibrillation (AF). AF in WPW syndrome is a potentially life-threatening arrhythmia. Radiofrequency catheter ablation is recommended in patients with AF in WPW syndrome. Atrioventricular nodal blockers can precipitate ventricular fibrillation and should not be used. We present patients with PSVT and AF in WPW syndrome who was treated with bisoprolol and flecainide.