This study examines sleep problems of children with Autism Spectrum Disorder (ASD), as reported by their parents. To investigate this issue a total of 35 children with ASD and 35 children of Typical Development (TD) were selected from northern Greece. A structured questionnaire (Williams et al., 2004) was used, a modified version of the questionnaire study conducted by the Kosair Children's Hospital Sleep Center (Gozal, 1998). Results show that children with ASD often experience sleep problems compared to TD individuals and also exhibit frequent awakenings during the night, difficulty in falling asleep, breathing concerns during sleep, morning headaches, sleepwalking, nightmares and fall asleep at school.