The first series of children with obstructive sleep apnoea syndrome was reported in 1976. Later it became apparent that children may have breathing disorders during sleep without frank apnoea or 'hypopnoeas'. This pattern could be detected by measuring the oesophageal pressure. This led to the concept of sleep-disordered breathing as a spectrum that combines obstructive sleep apnoea syndrome and the upper airway resistance syndrome. Studies that do not take into account this spectrum may misclassify symptomatic patients as 'primary snorers'. The exact prevalence of sleep-disordered breathing in children is unknown but may be as high as 11%. There is a familial predisposition to sleep-disordered breathing. Nasal obstruction and mouth breathing influence facial growth, which may further lead to difficulty in breathing while asleep. Symptoms include an increase in total sleep time, nonspecific behavioural difficulties, hyperactivity, irritability, bed-wetting and morning headaches. Clinical signs include failure to thrive, increased respiratory effort with nasal flaring and suprasternal or intercostal retractions. Also, abnormal paradoxical inward motion of the chest may occur during sleep. Excessive daytime sleepiness and obesity are not always present. Untreated children may develop cardiovascular complications. The condition is treatable with continuous or bilevel positive airway pressure, and may be cured with surgery.