Sleep disturbances are likely to be associated with emotional and behavioural problems in typically and atypically developing children. The study was aimed to evaluate sleep disturbances in children with autism spectrum disorder (ASD) and their associations with emotional/behavioural problems. The study comprised eighteen 5-year-old boys with diagnosed ASD. Control group was made up of matched 54 clinically healthy typically developing boys. The mothers were requested to fill in Child Sleep Habit Questionnaire (CSHQ) aimed to measure certain sleep troubles in children and the Achenbach Child Behaviour Check List (CBCL/1.5-5) aimed to find major emotional/behavioural disturbances. Children with ASD had significantly higher scores on sleep onset delay, night waking, parasomnia, sleep disordered breathing and daytime sleepiness scores. They also presented with statistically significantly higher values on affective, anxiety, pervasive developmental, attention deficit/hyperactivity and oppositional defiant problems subscales. Predictive analysis showed that anxiety problems could be finely predicted by ASD diagnosis, low IQ, sleep delay, sleep anxiety, and daytime sleepines. Affective problems could be predicted by ASD diagnosis, night waking and low IQ. So far as attention deficit/hyperactivity and oppositional defiant problems were concerned, these variables were most dependant on child IQ and gastrointestinal symptoms. Sleep disturbances in children with ASD are common and may be associated with emotional problems.