BACKGROUND: Nasal. intermittent positive pressure ventilation (NIPPV) is becoming more important as a mode of ventilation in premature neonates predisposed to development of bronchopulmonary dysplasia (BPD). To the best of our knowledge, there have been no detailed studies characterizing neonates who fail NIPPV. OBJECTIVE: To determine the differences between neonates who are successfully extubated to. NIPPV and those who require re-intubation from NIPPV, and the impact of timing of NIPPV failure on BPD rates. STUDY DESIGN: This was a retrospective cohort study in which we included infants with gestational age (GA) <= 28 weeks and birth weight <= 1000g. chi(2)-test, analysis of variance and multivariate logistic regression models were used. RESULTS: Two hundred and forty infants were studied; 180 failed NIPPV and of those, 33 (18%), 39 (22%) and 108 (60%) failed NIPPV within 0 to 6 h, >= 6 to 24 h and >= 24 h, respectively.. Female sex and increased weight were protective against NIPPV failure (adjusted odds ratio (95%. confidence interval): 0.28 (0.14 to 0.58), 0.04 (0.01 to 0.22)). Increased GA at extubation and female sex were both associated with increased time to failure (P=0.008, <0.001, respectively). Apnea was more likely the cause for failure >= 24 h (P = 0.015), whereas increased work of breathing/fraction of inspired oxygen requirements were more significant when NIPPV failure occurred earlier (P=0.001). Neonates who failed NIPPV within 24 h did not have any association with likelihood of developing. BPD or severity of BPD, after adjusting for confounding. variables. CONCLUSION: Significant differences in neonatal characteristics may help identify which neonates are more likely to fail NIPPV, and. their timing of failure.