Aim: To review the use of nasal CPAP (nCPAP) in infants with bronchiolitis.Methods: A prospective, multicentre, observational study was undertaken from 1st November 2008 to 28th February 2009. Seven Paediatric Units in the South of England participated in the study. Data was collected on indications for nCPAP, respiratory rate and blood gases prior to nCPAP, total number of days on nCPAP and length of hospital stay.Results: A total of 51 infants with the clinical diagnosis of bronchiolitis required nCPAP during the study period. The main indications were increased work of breathing (47.0%), apnoeas (39.2%) and increasing oxygen requirements (23.5%). Among them 16 were ex-preterm (31.37%).Prior to nCPAP the mean respiratory rate was 63/ min (range 28 to 120), mean oxygen saturations 85% (70 to 98%), mean pH 7.25 (7.03 to 7.36) and mean PCO2 10.42 (4.36 to 19.0).The average time on nCPAP was 2.6 days (2 hours to 11 days) and the average length of hospital stay was 10.96 days (5 to 22 days).11 out of the 51 infants failed trial on nCPAP requiring intubation (21.5%). The main indications were apnoeas (45.45%), CO2 retention (36.36%) and increasing work of breathing (36.36%).7 out of the 11 infants requiring intubation were expreterm (63.6%) and 8 had significant PCO2 rise (>8) prior to the trial of nCPAP (72.72%).Conclusions: nCPAP has a good success rate in bronchiolitis. In our study, predictive factors associated with nCPAP failure were prematurity and high CO2 retention prior to trial of nCPAP.