One of the most burdensome and profound complaint among parents of children with autism is disrupted sleep, with more than 40-80% of the children experiencing sleep problems compared with 25-40% in typically developing children. Consequence of disrupted sleep is potentially serious; it may exacerbate core ASD symptoms. Research is limited on sleep and its relation with behavioural problems and parental distress in low functioning autism. The main aim of the study is to assess the sleep problems and its relation with severity of autism, day time problem behavior and parental distress in children with low functioning autism. A descriptive cross sectional design was adopted for the study among 40 children aged between 6-16 years of age, recruited from selected special schools and autism centres in Kerala. Sleep problems, autism severity, problematic behavior and parental distress were assessed using Children’s sleep habit questionnaire (CSHQ), Social responsive scale (SRS), The Disruptive Behaviour Disorder Rating Scale, Parenting stress index respectively. Prevalence of sleep problems were more among children with low functioning autism. All the children in the study met the cut off score of sleep problems in CSHQ .But sleep problem was not correlated with severity of autism, problematic behaviours and parental distress. Findings showed that autism severity is related with parental stress (p=0.046) and problem behaviour (p<0.01) in children with autism. It was also observed that problematic behaviours in children is correlated with parental stress (p=0.019) .Study results emphasize the need for implementing interventions to reduce sleep problems, problematic behaviours and parental distress.