Sleep-related breathing disorders in children are a clinical problem which is more and more often diagnosed by doctors nowadays. They can be the basis for diagnosing obstructive sleep apnoea syndrome that causes a number of complications: lowering the quality of life, behavioural problems, complications involving cardiovascular system. The incidence of obstructive sleep apnoea syndrome in the paediatric population is estimated to be at the level of 2%. The symptoms of obstructive sleep apnoea syndrome can be divided into daytime and night ones. Night symptoms in children include: snoring, apnoea, breathing with open mouth (both during the day and at night), dry tongue and mouth during sleep, agitated sleep in unnatural positions. Among daytime symptoms of obstructive sleep apnoea syndrome there are: irritability, aggressiveness, hyperactivity, attention deficit disorder, delayed development and growth pattern (mainly failure to thrive), learning problems, morning headaches. Parents often do not connect the night and daytime symptoms with the possible development of obstructive sleep apnoea syndrome in their children. The main predisposing factor of obstructive sleep apnoea syndrome in children is adenotonsillar hypertrophy. Effective and in most cases preferred treatment for the management of obstructive sleep apnoea syndrome in children is adenotonsillectomy. Polysomnography and polygraphy are diagnostic tools helpful in the study of sleep-related disorders. The objective of this study was to systematise the knowledge on the epidemiology, aetiology, clinical image and prevention of obstructive sleep apnoea syndrome in children.