Introduction: Pulse oximetry is currently used to screen for obstructive sleep apnoea (OSA) in children. However, its use in infant has not yet been well studied. Aim: To develop a screening criterion using pulse oximetry to identify infant with probable OSA. Methods: A retrospective cross-sectional study including infants <1 year of age with features of upper airway obstruction or requiring home oxygen, to find associations between obstructive apnoea hypopnoea index (OAHI) in infant polysomnography (PSG) and parameters in pulse oximetry by Spearman Rho’s correlation. And using the parameter with strongest correlation, by receiver-operating characteristic (ROC) curve to identify a cut-off with highest Youden index to screen for probable OSA (OAHI >2 per hour). Results: A total of 27 infants were studied. The index of oxygen desaturation with SpO2 <90% per sampled hour (ODI<90%) had the best correlation with OAHI (r = 0.52, p = 0.005). Using the cut-off of ODI<90% more than 1.3 per hour, the sensitivity and specificity for identifying OAHI >2 per hour was 77% and 71% respectively. Conclusion: Infant pulse oximetry can be a useful tool to screen for probable infant OSA especially for paediatric units not offering infant PSG service.