Seven children who had partial arrest of the growth plate after neonatal arterial cannulation, developed obvious skeletal changes in adolescence. Cannulation of the femoral artery produced ischaemia which led to four cases of ipsilateral shortening of the lower limb and one of partial arrest of the proximal femoral physis with subsequent coxa valga. The two arrests in the upper limb affected the humerus, ulna and radius, and the radius alone, after cannulation of the brachial and radial arteries, respectively. These late effects of cannulation are not widely appreciated, and may occur as a result of thrombosis rather than extravasation.