Sudden cardiac death may occur in children with symptomatic and asymptomatic Wolff-Parkinson-White syndrome (WPWS). Symptomatic patients are usually treated with antiarrhythmic drugs until ablation of an accessory pathway (AP) could be performed. The objective of this study was to review the safety and efficacy of flecainide in the treatment of children with symptomatic WPWS. Twenty-two children (14 male) with WPWS and without structural heart disease were studied. AP location was achieved by electrophysiological testing or 12-lead electrocardiogram tracing. Symptomatic children (i.e., those frequent palpitations or supraventricular tachycardia episodes) received flecainide. Patients were followed-up for an average of 3.4years until ablation of AP. Eighteen children reported clinical symptoms when first diagnosed, but only 13 initiated treatment during 16.23months (range 1-55). Flecainide was effective in all patients: Seven became asymptomatic, and six experimented isolated episodes of palpitations. One child experienced hair loss as a side effect. AP location was as follows: left free wall (n=7), right free wall (n=4), posteroseptal (n=8), and anteroseptal (n=4). Ablation was performed without complications in 13 children. Symptomatic WPWS in children can be treated safely and efficiently with flecainide. It represents a good alternative therapy until AP ablation can be performed.