PURPOSE: We examined the respiratory morbidities in late-preterm infants compared to those of the early-preterm infants and term infants throughout the first year of life. METHODS: Data were retrospectively collected for 87 late-preterm, 72 early-preterm, and 608 term infants who were admitted to NICU and the nursery of Busan St. Mary's Medical Center from Jan 2007 to Oct 2009. RESULTS: There were significant differences in the proportions of the out-born infants, twin pregnancy, small for gestational age, and Caesarean section in the three groups (P<0.05). Late-preterm and early-preterm infants had longer duration of hospitalization, larger proportions of respiratory distress syndrome, mechanical ventilation at birth, oxygen therapy after 48 hours of birth, oxygen dependency at 28 days, and continuous positive airway pressure support at 28 days compared to term infants during the neonatal period (P=0.000). Late-preterm infants and early-preterm infants were re-admitted more often than term infants during the first year of life (P=0.000). Also Late-preterm and early-preterm infants had increased chance of respiratory tract illness than term infants (P=0.001). CONCLUSION: In this study, we demonstrated that there are higher chances of respiratory morbidities in the late-preterm infants than the term infants either during the neonatal period or throughout the first year of life, although early-preterm infants showed greatest respiratory morbidities.