Preterm birth is a major public-health issue because of its increasing incidence combined with the frequent occurrence of subsequent behavioral, neurological, and psychiatric challenges faced by surviving infants. Approximately 10-15% of very preterm children (born less than 30 weeks gestational age) develop cerebral palsy, and 30-60% of them experience cognitive impairments. These adverse outcomes are related to a confluence of abnormal brain development along with white (WM) and gray matter (GM) injury sustained during the neonatal period. It is becoming apparent that the extra-uterine environment during this critical period (24-40 weeks gestation) in brain development has a profound and long lasting impact on the premature infant. Magnetic resonance imaging in the neonatal period and infancy provides a non-invasive, "in vivo" assessment of brain development and extent of brain injury. This not only helps understand the extent and timing of injury but also identifies infants who may benefit from early intervention to minimize the impact of the injury. (Contains 1 figure.)