Study Objectives: To survey the prevalence of parasomnias in a population of children aged 7 to 11 years and to determine whether parasomnias are associated with medical and neurobehavioral properties. Design: Parents and children completed a pediatric sleep questionnaire that contains 27 items developed by the authors to assess parasomnias in children. Parents and children were also interviewed about the children's medical and sociofamilial history, schooling, psychological difficulties, medication intake, and the history of psychomotor and psychosocial development. Setting: NA Participants: 971 preadolescent school-aged children from 4 locations in Turkey participated in the study. Results: We found a 14.4% prevalence of parasomnia in preadolescent school-aged children. Almost every sixth child had about at least 1 parasomnia. When we examined parasomnias separately, bruxism, nocturnal enuresis, and night terrors were the most common parasomnias among both girls and boys. The prevalence of parasomnias was higher in the 9-and 10-year-old age groups than in the other age groups. Girls and boys did not differ. Children with parasomnias had higher rates of past physical illness, delays in toilet raining, behavior disturbances, adjustment problems, and learning difficulties. Conclusions: These results suggest that the prevalence of parasomnias was high in the 9- and 10-year-old age groups. Parasomnias are associated with a history of physical illness and neurobehavioral abnormalities.