During the last several decades, the number of preterm infants has increased, and their survival rate has improved owing to advances in perinatal care. As more preterm infants survive, many studies examine their neurodevelopmental outcomes. This study aimed to summarize the neurodevelopmental outcomes of preterm infants according to gestational age at birth using a recently published meta-analysis. The prevalence of neurodevelopmental impairment (NDI) and behavioral disorders decreased as gestational age and birth weight increased. Recent studies reported that proactive neonatal treatment of peri-viable preterm infants (gestational age, 22-24 weeks) could improve their prognosis. Moderate and late preterm infants reportedly have less severe disease than very preterm infants; nonetheless, they still experience adverse neurodevelopmental outcomes compared to term infants. Neonatal morbidities such as bronchopulmonary dysplasia and retinopathy of prematurity are associated with poor neurodevelopmental outcomes. Despite improvements in neonatal care, prematurity is still associated with poor neurodevelopmental outcomes. To ensure timely intervention, the establishment of a follow-up system for premature infants is necessary.