Abstract. BACKGROUND: In spite of widespread use of nasal CPAP there are comparatively few studies to guide the choice of nasal prongs. OBJECTIVES: To determine whether the Fisher & Paykel Healthcare (FPH) neonatal continuous positive airway pressure (CPAP) interface was effective in providing bubble CPAP when compared to the Hudson prong interface. METHODS: The study was a randomized cross-over study of twenty newborn infants 500 g or more requiring CPAP for respiratory support at birth. Infants were randomized to either the Fisher & Paykel Healthcare or Hudson CPAP interface for twenty four hours. Crossover between interfaces occurred after subsequent twenty four hour periods. The primary outcome was the provision of desired CPAP pressures, defined as provision of CPAP within±one cm H2O of set pressure. RESULTS: The percentage time CPAP was within±one cm H2O of set pressure was 66.5% for the Hudson and 71.8% for the FPH interface (p = 0.66). Oxygen saturations for the Hudson interface were in target range for a median of 97.8% of the time, and, with the FPH interface, for a median of 98.2% of the time (p = 0.76). Clinically significant differences in primary or secondary outcomes between the two groups were not detected. CONCLUSIONS: The nasal CPAP interfaces studied were equally effective in achieving desired bubble CPAP pressures and target saturations.