The pathophysiology of obstructive sleep apnoea (OSA), a common condition in children, is poorly understood. While adenotonsillar hypertrophy is certainly a major contributor, other factors are needed for OSA to develop. OSA has been associated with substantial morbidities primarily affecting cardiovascular and neurobehavioural systems which may not be completely reversed with appropriate treatment. This paper reviews the available information and attempts to provide the rationale for early diagnosis and treatment of OSA in children.