Introduction: Multidisciplinary interprofessional, interorganizational and intersectoral collaboration is considered key to meet the complex needs of persons with an autism spectrum disorder (ASD). However, the “institutional field” potentially challenges the integration of care for persons with ASD in Flanders. This contribution explores how regulations affect adequate trajectories of care for persons with ASD. Methods: An inventory was made of publicly accredited and funded organisations providing (early) detection, diagnostics, treatment and care for children, adolescents and adults with ASD. A qualitative thematic analysis was done of the criteria put forward by Federal and Flanders’ Community/Regional regulations for organisations. This analysis was validated and complemented with information from an expert panel in order to understand barriers and facilitators for collaboration. Results: The inventory learns that more types of organisations in different policy domains provide services for children and adolescents with ASD compared to adults. The regulations setting the criteria for target group, type of ASD related activity, the professional team, access (financial and by referral or not) and organizational characteristics differ according to the sector (health, welfare, persons with disability). The regulations also differ in the level of detail of criteria. Some organisations (and regulations) are dedicated for persons with ASD, while other organisations provide services for a wider range of disorders, including ASD. Discussion: After the 6th state reform in Belgium, Flanders is seeking for an interorganizational collaboration model providing ASD services. This project studies the possibilities for a “mandated interorganizational network” in which general and specialized care are provided in an effective and efficient way, including an accessible regional system of care for persons with ASD. Therefore we need to understand the newly emerging institutional field. At this stage we only performed a rather ...