Laryngeal chemoreflexes (LCR) are triggered by the contact of assorted liquids with the laryngeal mucosa. In the neonatal period, the immature LCR consist primarily of apnea and bradycardia, which at times can be life-threatening. The aim of this study was to assess LCR induction in non-sedated, newborn full term lambs by several acid solutions, in comparison to distilled water and saline. Twelve lambs were instrumented for recording of glottal adductor and diaphragm EMG, electroencephalogram, eye movements, heart rate, systemic arterial pressure and respiratory movements. LCR were induced during quiet sleep by the injection (0.5 ml) of saline, distilled water or two acid solutions (HCl and citric acid, pH 2, diluted in either water or saline). A chronic supraglottal catheter was used to inject the solutions in a random order. Distilled water and acid solutions did not induce any significant decrease in heart rate or respiratory rate. However, significant lower airway protective responses (swallowing, cough and arousal) were observed after distilled water and especially acid solution administration. In conclusion, LCR in full-term lambs, particularly with acid solutions, are merely characterized by lower airway protective responses resembling mature LCR reported in adult mammals.