 The title of this acute, open-label pilot study is Controlled Release Melatonin Melatonin CR for the treatment of impaired sleep maintenance ISM in 4-8 year old children with autism spectrum disorders ASD. Maintenance of sleep is a significant challenge in the treatment of children with neurodevelopmental disabilities including ASDs. Night awakening or early morning waking can have detrimental effects on these childrens daytime behavior and the functioning of their household. Sleep problems in the ASD population are generally managed first with behavioral interventions and, when these are not successful, pharmacologic therapy. Most medications effect sleep onset and not sleep maintenance. This study investigates the effectiveness of Melatonin CR for managing ISM in 4-8 year old children with ASD. Twenty patients will be recruited from the DevelopmentalBehavioral Pediatrics Clinic at the Munroe Meyer Institute at the University of Nebraska Medical Center. Inclusion criteria are male and female children ages 4-8 years with a diagnosis of an ASD, including Pervasive Developmental Disorder NOS PDD, NOS, Aspergers Syndrome, or Autistic Disorder, parentguardian consent for participation, stable psychotropic medication treatment for at least 4 weeks, and a documented history of ISM based on parent-report, somnolog and Child Sleep Habits Questionnaire CSHQ, and a clinician rating of 4 moderately ill on the Clinical Global Impression-Severity CGI-S Scale. Patients will be excluded if they have been treated with Melatonin or Melatonin CR in the past month, failed treatment with Melatonin CR, or if they have a previously un-evaluated medical condition which may be causing the ISM. Following the completion of a somnolog and standardized questionnaires, the patients will be treated for 10-14 days with melatonin CR. Somnologs will be completed during treatment, and standardized parent questionnaires, CGI-S, and adverse event collection will be repeated at the end of Melatonin CR therapy. Response will be defined as a Clinical Global Impression-Improvement CGI-I score of 1 or 2 much or very much improved. These will be compared to baseline ratings. Following the completion of the study protocol, all patients will continue to be followed in the Developmental Pediatrics clinic. Data from this acute pilot trial can be used to evaluate the appropriateness of a larger study to determine optimal therapy for patients with ASD and ISM. 