Employing a mixed methods approach, this study examined the knowledge and information Ontario physicians have concerning Autism Spectrum Disorder (ASD). Physicians are at the front line when it comes to identifying ASD. The Healthcare Professional Questionnaire was filled out by 46 physicians and 16 filled out the Knowledge about Childhood Autism among Health Workers Questionnaire (KCAHW) before being asked to participate in a semi-structured interview in which 7 participated. Paediatricians and psychiatrist reported having the highest levels of knowledge. Findings revealed that physicians are lacking in information regarding some early signs (i.e. social smiling = 50%), added diagnostic criteria (i.e. hypo-reactivity to sensory information = 56%), and the prevalence rate of ASD (average estimate of 1 in 1109). Additionally, exposure to individuals with ASD was found to be a facilitator to knowledge acquisition regarding ASD. The physicians recommended a road map method to disseminate information and increase knowledge and awareness. Implications of the findings include what areas of knowledge and information need to be increased, and how knowledge and competency can be increased, to better care for this population.