The purpose of this study was to expand the American Academy of Pediatrics' (AAP) car safety seat testing recommendation to include high-risk infants following cardiac surgery. Car safety seat testing (< or =4 days prior to discharge) was retrospectively reviewed for 66 postoperative infants. Car safety seat testing was performed according to AAP guidelines. Failure of the test was defined as the occurrence of apnea, bradycardia, or oxygen desaturation. Average birth weight was 3.1 +/- 0.5 kg. Two patients were born <37 weeks of gestation. Surgical procedures included modified Blalock-Taussig shunt (15), arterial switch operation (12), Norwood-Sano modification (11), coarctation repair (8), repair of tetralogy of Fallot (6), repair of truncus arteriosus (4), repair of total anomalous pulmonary venous return (3), pacemaker (2), repair of interrupted aortic arch and ventricular septal defect (VSD) (1), repair of coarctation/VSD (1), orthotopic heart transplant (1), repair of VSD (1), and patent ductus arteriosus ligation (1). Average age at discharge was 28 +/- 21 days. Four patients (6%) failed car safety seat testing secondary to a decrease in oxygen saturation. One of four passed on retesting after parental education; three of 4 (75%) were discharged home in a supine car safety seat. There was no relationship between the type of surgery and car safety seat test failure. It may be beneficial to extend the AAP recommendations for car safety seat testing to include this high-risk patient population.