Utilization of nitric oxide therapy in the neonatal period has been related to a trend towards short term improvements in respiratory and neurological outcome at 28 days postnatal age or 36 weeks postconceptional age. A two year follow-up in children treated soon after birth with NO in the neonatal period, suggests that a significant improvement in neurodevelopmental outcome might occur. No long term evaluation on respiratory outcome has yet been done. This study aims to evaluate respiratory and neurodevelopmental outcome at 6 years of age in children born very prematurely, some of them having had Nitric Oxide as a rescue treatment for respiratory distress syndrome.