Introduction: Autism spectrum disorder is a serious neuro developmental disorder that impairs a child's ability to communicate and interact with others. Each child with Autism spectrum disorder is likely to have a unique pattern of behaviour and level of severity - from low functioning to high functioning. Parents are usually the first to notice unusual behaviours in their child, although they may not realize the specific nature or degree of the problem. Knowledge, attitude and practice of parents/primary care givers towards children with autism spectrum disorder are important factors in promoting health and wellness of children. Objectives: To assess the level of knowledge, attitude and practice among primary caregivers regarding care of children with autism spectrum disorder and to evaluate the effectiveness of video assisted teaching regarding care of children with autism spectrum disorder on knowledge, attitude and practice among primary care givers. To associate the level of knowledge, attitude and practice regarding care of children with autism spectrum disorder with selected demographic variables. Methodology: Pre experimental research design with one group pre-test post-test was adopted. Sixty primary caregivers were selected through purposive sampling. Video assisted teaching was given to primary caregivers. Data collection was done before and after the video assisted teaching programme using structured questionnaire which consists of 57 questions. Results: The result of the study showed that the post test level of knowledge (16.67±1.79) attitude (16.57±4.16) and practice (29.5±6.04) among primary caregivers of children with autism spectrum disorder was significantly high (p=0.001) when compared to pre test level. Conclusion: This study revealed that video assisted teaching is effective in enhancing the knowledge of primary caregivers about autism spectrum disorder. The study helps to make a positive attitude among primary caregivers towards caring the children with autism spectrum disorder.