GER has been shown to decrease in response to positive pressure ventilation. We studied 16 premature neonates who had just been weaned from NCPAP, to assess the effect of NCPAP at +5 cms H2O on the amount of GER, AP and BR. One group of 8 (control group, CON) had 16-hr data recordings made on two successive days while the other 8 (experimental group, EXP) had a baseline 16-hr data recording on day 1 and a second data recording while on NCPAP on day 2. There were no differences between EXP and CON in birthweight(0.97 vs 0.90 kg), gestational age (27.6 vs 26.1 wks) or age at study (40 vs 36 days). Changes in GER, reflected by time with esophageal pH<4 from day 1 to 2 (day 2 - day 1 scores), were not significant and were not different for EXP and CON (-106 vs -39 min). Changes in AP, measured by chest wall impedance, were not different for EXP and CON (-9 vs +8 sec for episodes of at least 10 sec duration). However, the duration of BR did decrease for EXP compared to CON (-4.4 vs +2.8 sec/episode of at least 5 sec of heart rate<100, p<0.05). Although NCPAP does not seem to alter the occurrence of GER or AP, the decrease in duration of BR during NCPAP is consistent with published data suggesting NCPAP may reduce the incidence of obstructive AP.