The interest in paediatric sleep disorders over the last few decades has had its main focus on the sudden infant death syndrome (SIDS) - healthy infants who go to sleep and never wake up again. Overall, this is the most dramatic form of paediatric sleep disordered breathing. By contrast, classical presentations of sleep disordered breathing in children, such as snoring and obstructive sleep apnoea as well as their clinical implications have been greatly neglected and underestimated in the past. In contrast to snoring in adults, snoring in children has so far generally been regarded as noisy breathing with no significant impact on the general health of children. This is also to a lesser extent true for obstructive sleep apnoea syndrome (OSAS). The sometimes dramatic complications of OSAS, such as cor pulmonale and developmental retardation have at least indicated that OSAS in children is important and may have a great impact on the general health of children. This has led to an increased interest from a clinical as well as a scientific point of view with some important findings, mainly that sleep disordered breathing in childhood varies from sleep disordered breathing in adulthood and that even mild to moderate disease has a huge impact on the general health of children, mainly on neurocognitive development.