The most common anomaly of the aortic arch is the occurrence of a left aortic arch with an aberrant right subclavian artery. Other, less common anomalies have also been described. These include the occurrence of a right aortic arch with an aberrant left subclavian artery that, in addition, has a diverticulum at its site of origin known as Kommerell's diverticulum. All cases described in the literature have occurred in individuals younger than 35 years of age, generally with symptoms related to tracheal or esophageal compression. We present the case of a patient diagnosed by chance with this rare anomaly at 75 years of age.