Early childhood intervention is associated with the right of every child with developmental disabilities and his family to support, and is implemented through a number of systems - the healthcare system, the social welfare system and the non-governmental sector. Inter / transdisciplinary co-operation in early intervention practices has proven to be the best approach to designing a child program and providing professional family support, services are coordinated and make a coherent whole. The paper presents the results of the research aiming to gain insight into inter / transdisciplinary experience in the field of early intervention from the perspective of experts (N = 13) who work in early intervention. Experts who participated in the research see their role and the role of their profession in inter / transdisciplinary work through: working with the family, working with a child, collaborating with other experts and expert work. Their experiences in inter / transdisciplinary approaches in the area of early intervention are described by the participants as a specific approach to the child and family, team work experience and cross-sectoral experience. Experts participating in the research are satisfied with an inter / transdisciplinary approach. Accordingly, the main recommendations for improving inter / transdisciplinary cooperation in early intervention in Croatia are: decentralization of early intervention services, introduction of inter-transdisciplinarity in early intervention practices as models of service delivery and improvement of professional staff. Social workers working in early intervention are increasingly beginning to perceive themselves as indispensable members of the early intervention team with the role of coordinators of the early support, providers of information and counsellors. Responses from experts point out that early intervention in Croatia has progressed but needs to continue to work to transform early intervention into a comprehensive system, inter / transdisciplinarity as a form of cooperation is recognized as good and desirable in order to facilitate the purpose of early intervention in childhood.