Sleep disorders in children are diverse in type, common, often serious in their effects yet neglected in professional education. They complicate many psychiatric disorders and can cause various cognitive and behavioural problems as well as more widespread difficulties in the family as a whole. Accurate assessment allows an appropriate choice from the various types of treatments that are now available but often under used. Diagnostic points and treatment approaches are outlined for the three main categories of childhood sleep disorder: sleeplessness; excessive sleepiness; and episodic disturbances related to sleep (parasomnias). The need for more widespread awareness of and provision for sleep disorders is emphasized.