The origin of the circumflex coronary artery from the right sinus of Valsalva is generally considered a benign anomaly. Herein we report the sudden unexpected death of a 6-year-old boy who died after jumping into a swimming pool and whose only pathologic finding was this usually inconsequential coronary artery anomaly. A discussion of the pathophysiology of the disorder and a literature review are included. This is the youngest patient to die with this entity.