Purpose: Flecainide is a class 1C antiarrhythmic drug, especially used for the management of supraventricular arrhythmia. Flecainide also has a recognized proarrhythmic effect in all age groups of adult patients treated for ventricular tachycardia. It is used to treat a variety of cardiac arrhythmias including paroxysmal fibrillation, Paroxysmal Supraventricular tachycardia and ventricular tachycardia. Flecainide works by regulating the flow of sodium in the heart, causing prolongation of the cardiac action potential. The proarrhythmic effects however noted are not widely reported. Case report: We report a case of paroxysmal atrial fibrillation with structurally normal heart who was treated with oral Flecainide. Despite subjective improvement and no adverse events [QTc prolongation] a repeat holter detected him to have multiple short non sustained ventricular arrhythmias. Results: Development of ventricular arrhythmias, salvos &non sustained ventricular tachycardia after a month of initiation of oral Flecainide detected by 24 hours ECG holter lead to discontinuation of Flecainide and subsequent early electro physiological studies and successful ablation. Conclusion: Initiation of oral Flecainide in a case of atrial fibrillation with subjective improvement and regular ECG monitoring, no QTc prolongation can still lead to development of dangerous ventricular arrhythmias. A cautious approach and thorough investigations and follow up are recommended.