A 35-year-old man was referred to his primary care physician for evaluation of previously unknown hypertension that had been identified during a medical screening for his rugby team. The patient was asymptomatic. The blood pressure was 146/89 mm Hg in the left arm, 146/99 mm Hg in the right arm, 104/83 mm Hg in the left leg, and 109/90 mm Hg in the right leg. On physical examination, a radial–femoral delay was present. A chest radiograph showed notching of posterior ribs 3 through 8 (Panel A, arrows) and widened paratracheal stripes (Panel A, asterisks). Computed tomographic (CT) angiography of the chest revealed coarctation of the descending aorta, with the isthmus measuring 3 mm in diameter (reference range for the patient’s age and size, 18 to 25) (Panel B, arrow). CT angiography also showed extensive collateral arterial circulation in the soft tissues (Panels C and D, white arrows), along the trachea (which accounted for the paratracheal stripes seen on chest radiography) (Panel C, dashed box), and in the intercostal spaces (which accounted for the notching of the ribs seen on chest radiography) (Panel D, black arrows). A transthoracic echocardiogram showed left ventricular hypertrophy and a pressure gradient of 25 mm Hg across the coarctation. No other cardiac abnormalities were identified. Percutaneous stenting of the aortic coarctation was performed without complications. At a follow-up visit 1 month after the procedure, the patient’s blood pressure had improved. At a 3-month follow-up visit, repeat imaging showed a marked decrease in collateral arterial circulation.