Background of the study: Various risk factors have been reported in the development of Autism spectrum Disorder. The aim of our study is to explore the demographic and perinatal risk factors implicated in the development of ASD. A retrospective study was conducted with data of 49 children with ASD and found that total 71.3% of children were male 73.5% were in rst birth order. Out of 49 children 53.1% had history of Lower Segment Caesarean Section (LSCS). Indication of LSCS due to various obstetric or perinatal risk factors were reported in 17 cases. Three children had history of low birth weight with history of admission into Neonatal ICU. The study also explore the various co morbidity and found that ADHD (20.4%) was most common comorbidity followed by Mental retardation(18.4%), ADHD and MR(12.2%), seizure disorder and MR (8.2 %). This study found that male gender, rst birth order and perinatal risk factors are implicated in the development of Autism spectrum Disorder and majority of them have one or more another neuro developmental disorder as a comorbidity.