Nasal ventilation is increasingly used to reduce invasive ventilation in preterm infants. The effects of nasal ventilation and the advantages of synchronized nasal ventilation have not been fully evaluated. The objective was to compare the short-term effects of nasal intermittent mandatory ventilation (NIMV) and synchronized NIMV (S-NIMV) with nasal continuous positive airway pressure (NCPAP) on ventilation, gas exchange, and infant-ventilator interaction. Sixteen clinically stable preterm infants requiring NCPAP (GA, 27.6 ± 2.3 wk; birthweight (BW), 993 ± 248 g; and age, 15 ± 14 d) were exposed to NCPAP, NIMV at 20/min, NIMV at 40/min, S-NIMV at 20/min, and S-NIMV at 40/min for 1 h each (Infant-Star ventilator), in random order. Tidal volume, minute ventilation, and gas exchange did not differ significantly between NCPAP, NIMV, and S-NIMV. Inspiratory effort decreased during S-NIMV compared with NCPAP and NIMV, whereas inspiratory effort during NIMV did not differ from NCPAP. Active expiratory effort and expiratory duration increased during NIMV. Chest wall distortion, apnea and hypoxemia spells, abdominal girth, and comfort did not differ. In conclusion, there were no short-term benefits on ventilation and gas exchange of nasal ventilation compared with NCPAP in clinically stable preterm infants. However, synchronized nasal ventilation reduced breathing effort and resulted in better infant-ventilator interaction than nonsynchronized nasal ventilation.