Saphenous vein graft, neonatal arterial injury, catheterizationTwo neonates with congenital heart disease, one and thirty-one days old respectively, suffered inadvertent arterial injury from cardiac catheterization. Both insults resulted in unrecognized avulsion of the external iliac artery from its origin. The patients quickly decompensated, with their right lower extremities becoming critically ischemic. In both cases, segments of reversed greater saphenous vein were used as interposition grafts from the common iliac artery to the common femoral artery. Reperfusion of the right foot was immediate for the one-day-old. She is now three years old and able to run, but is followed for a mild limb length discrepancy. The 31-day-old had restoration of flow to the right limb; however, the foot remained ischemic and eventually required transmetatarsal amputation. She is now 16 months old and able to crawl; she also is followed for limb length discrepancy. Without vein grafting, both infants would likely have lost their affected limbs, and possibly lost their lives. These cases advocate for microsurgical repair of arterial injuries in even the youngest patients, and promote the use of vein grafts when direct anastomosis is not feasible.