Background: Extremely preterm (gestational age (GA) <28 weeks) and extremely low birth weight (ELBW) infants (<1000g) are at risk to develop respiratory morbidities like respiratory distress syndrome (RDS), bronchopulmonary dysplasia (BPD) and pneumothorax. The delivery method also influences respiratory outcomes, with cesarean sections (CS) being associated with a higher incidence of RDS, pneumothorax and ventilatory treatment. To develop new preventive or early respiratory treatment strategies for high-risk neonates, knowledge about risk factors for respiratory outcomes in this group is necessary. This study aims to investigate the association between the delivery method and respiratory outcomes in extremely preterm and ELBW infants.Methods: We performed a retrospective patient record cohort study of all extremely preterm and/or ELBW neonates born between 2000-2003 in a tertiary center in Maastricht, the Netherlands. Differences in RDS, BPD, pneumothorax, invasive mechanical ventilation (MV), continuous positive airway pressure (CPAP), nasal oxygen, duration of invasive MV, CPAP and total respiratory support, nitric oxide, surfactant and postnatal steroids with pulmonary indication between vaginal delivery (VD) and CS were assessed.Results: A total of 172 infants were included. The CS group (n=119) had a higher mean GA, percentage males and prevalence of multiple gestations compared to the VD group (n=53) (p<0.05). Furthermore, birth weight, birth weight standard deviation score (SDS) and weight at discharge were lower in the CS group (p<0.05). Fetal distress and moderate 1-minute Apgar scores (4-6) were more common in the CS group, as was premature rupture of membranes. Low 1-minute Apgar scores (0-3), persistent ductus arteriosus and intraventricular hemorrhage occurred more frequently in the VD group, as did pre-eclampsia or ‘hemolysis elevated liver enzymes low platelet count’-syndrome. After correcting for GA and birth weight SDS, a significant association between CS and receiving surfactant was found. Other primary respiratory outcomes and treatments did not show any associations. Conclusions: After correcting for GA and birth weight SDS, the method of delivery is not associated with adverse respiratory outcomes in extremely preterm and ELBW infants. Due to changes in standard operating procedures, additional prospective research should focus on infants born more recently.Trial registration: Not applicable.