Eighty-eight children with autism, living in a suburb of Tokyo, were examined by questionnaire from 21 July to 31 August. Experienced sleep disorders were observed in 56 children; 44 of whom had sleep disorders before 3 years old. The average age when sleep disorders were seen to have stopped was 5 years old. The most common problem was difficulty falling sleep (n=23), followed by frequent awakening during sleep time (n=19), then early morning awakening (n=11). Bed-wetting was observed in 22 children.