Pulmonary sequestration is a rare bronchopulmonary foregut malformation, for which the arterial blood supply is usually derived from the descending thoracic or abdominal aorta. A 5-week-old infant is described with an extralobar pulmonary sequestration supplied by a large artery originating from the innominate artery, an arrangement only described once previously. Helical CT scan now makes arteriography unnecessary in the evaluation of these malformations.