The subclavian flap aortoplasty gives excellent short-term and medium-term results when performed on infants with coarctation of the aorta. This study was devised to determine whether there were any detrimental effects to the sacrifice of the left subclavian artery in infancy. Sixteen patients were studied 2 to 9 years post-operatively. Clinical evaluation revealed no major symptoms in the left upper limb. However, in seven children, minor symptoms had been noted by the parents. Anthropometric measurements revealed a shortening of the left upper limb in all patients; when these measurements were compared with those in normal subjects, the shortening was localized to the left upper arm. Four papers which mention the effect on the left arm of ligation of the subclavian artery in childhood during the Blalock-Taussig operation are discussed. It is concluded that the excellent results from the subclavian flap aortoplasty are not compromised by the minor effects of ligating the left subclavian artery in infancy.