Over a 12-month period, 28 neonatal patients in respiratory failure were supported with extracorporeal membrane oxygenation (ECMO), and 11 of these underwent successful repair of the right carotid artery post-ECMO. Nine of 11 were studied with duplex color-flow Doppler imaging between 14 and 109 days of age and again at 1 year of age. A velocity ratio (A/B) of the peak systolic velocity above the level of the anastomosis to the peak systolic velocity below the anastomosis was measured to assess the degree of stenosis, if any, at the repair site. Antegrade flow through the carotid was detected post-ECMO in 8 of 9 infants, and antegrade and retrograde flow was documented in 1 infant. A/B ratios ranged from 1.00 to 8.60 (A/B ratio of 1 is normal; 2.0 indicates at least a 50% obstruction to flow). Four of 9 patients had ratios greater than 2.0, and 8 of 9 exhibited some evidence of obstruction. Follow-up scans were performed on 8 of 9 infants between 12 and 18 months of age. All infants examined showed marked improvement in A/B ratio and patency of the vessel, documenting that initial narrowing of the vessel is reversible. No infant had evidence of embolic phenomena to the right side of the brain by magnetic resonance imaging. Repair of the common carotid artery post-ECMO is technically feasible without increasing the risk of brain injury.