OBJECTIVES:To determine the influence of modern airway clearance techniques using assisted autogenic drainage (AAD), whether or not combined with bouncing, on acid gastro-oesophageal reflux (GOR) in infants <1 year. Methods: In this controlled trial with intra-subject design infants were studied using oesophageal pH monitoring over 24 h, during which they received one 15 min session of bouncing, AAD or bouncing combined with AAD (BAAD). The number of reflux episodes (RE) and the refluxindex (RI) were the outcome measures. The results obtained during (T15) and 15 min after the intervention (T30) were compared to a period of 15 min before treatment (T0). Results: The results of 150 infants, evenly distributed over the three treatment groups, were analyzed. No significant differences were found in number of RE at T15 and T30 compared to T0 in the bouncing group (P = 0.42), the AAD group (P = 0.14), and the BAAD group (P = 0.91). RI was significantly lower in the AAD group at T15 compared to T0 (P < 0.01). No differences in RI were found in the bouncing group (P = 0.28), nor in the BAAD group (P = 0.81).