Wolff-Parkinson-White syndrome is rarely associated with a right atrial aneurysm. However, when such a condition occurs, it will be hard to manage since pre-excitation will be induced as long as the aneurysm persists. A 14-year-old female patient received emergency treatment for irregular wide QRS complex tachycardia in our center, and a pre-excitation pattern was then observed on the surface electrocardiogram. An initial electrophysiological study revealed a high-risk right posterior accessory pathway that was resistant to both radiofrequency and irrigated radiofrequency ablations. Subsequently, fluoroscopy showed that this was due to a right atrial aneurysm. Although successful ablation with irrigated radiofrequency was performed in the second procedure, the procedure was considered suboptimal due to the association of aneurysm. Accordingly, we initiated anti-thrombotic and anti-arrhythmic drug therapy. We decided to omit surgery and followed the case under medical treatment for 2 years without complications. Here, we report this rare coexistence and our treatment approach in detail.