Long-term developmental outcome of the prematurely born is generally related to birth weight as a reflection of gestational age: The more immature the infant, the greater the risk of abnormal developmental outcome. Due to improvements in fetal and neonatal care over the past 25 years, developmental outcome of the preterm group has steadily improved, now approaching the expected outcome for term neonates for those born weighing over 1,000 g. For the group of very immature infants (birth weight less than 1,000 g) abnormal developmental outcome remains a significant risk. For any individual preterm infant, long-term developmental outcome is generally related to the severity and duration of initial illness and the postdischarge environment. Specific causation of developmental abnormality in a particular infant is usually speculative. The overall improvement in the long-term outcome for preterm infants has been gained at great cost in medical resources and is accompanied by emotional costs to families that remain unmeasured. The key to further reducing the risk of abnormal developmental outcome remains the prevention of prematurity. Until that can be accomplished, continued meticulous attention to all the details of superb fetal and neonatal intensive care must be exercised to minimize the risk of handicap in this vulnerable group of patients.