Hypoxia can be an early sign of infection, respiratory or circulatory pathology in infants. Since it is difficult to properly judge oxygen saturation solely by skin discoloration, it is preferable to objectify this parameter via pulse oximetry (PO). PO in young infants has shown to be feasible in the primary care setting. Even though PO is broadly used by general practitioners (GPs) in older children and adults, it is rarely performed in young infants. We present three patients, aged 0 to 6 months, who were seen in primary care, where PO was an important factor in determining the level of illness. These patients illustrate the value of PO in infants by GPs in estimating illness severity, need for referral and mode of transport to the emergency department. We therefore advocate for GPs to obtain adequate equipment for PO in infants.