OBJECTIVES: There are few economic evaluations of strategies for screening, diagnosing, and treating autism spectrum disorder (ASD). The objective of this study was to create a discrete event simulation (DES) model of the pathway of care for children with suspected ASD up to age 6. This model will be used to perform economic evaluations of screening protocols, diagnostic tests and treatments for ASD. METHODS: A DES model was conceived to simulate a Canadian population of children with suspected ASD. Attributes important for simulation of entities were identified from the literature and expert opinion. Important categories of attributes included ASD risk factors, ASD co-morbidities, measures of development, and measures of severity of ASD. The pathway of care was created with review of current practice guidelines as well as consultation with developmental pediatricians. Queuing for screening, diagnosis, and treatment comes from entities accessing limited resources over a period of time. We will use calibration techniques to set resource and time limits to match the wait times reported in the literature. RESULTS: A DES model was built for children with suspected ASD up to age 6. The DES model addresses population heterogeneity by including risk factors such as gender, autistic siblings, and older parents, genetic co-morbidities, and physical and psychological co-morbidities. The DES model simulates outcomes in terms of ASD severity, IQ, and language skills. The DES model addresses the issues of wait times that are relevant in ASD screening, diagnosis, and treatment by having entities queue for limited resources. CONCLUSIONS: The DES modelling approach is well-suited to modelling the pathway of care for ASD patients. Patients with ASD have a wide variety of disabilities and co-morbidities that can be captured in DES modelling. DES modelling is also able to address issues of wait times that are prevalent in ASD screening, diagnosis, and treatment.