Objective: To describe the changes in functioning of the rehabilitation team induced by the Rehabilitation Activities Profile for children (Children's RAP), an instrument designed to improve interdisciplinary communication in paediatric rehabilitation. Design: Multiple case-study design. Subjects: Seven paediatric rehabilitation teams. Intervention: A two-year project to develop and implement the Children's RAP. Data collection: During the project, data were gathered from observations, documents and informal interviews. After the project, formal interviews were held with team members and parents, and a focus group meeting with representatives of the teams was organized. Data analysis: Data were analysed by the method of analytic induction. The analysis was checked by an independent researcher. The preliminary results and conclusions were discussed in detail with participating teams. Results: Development and implementation, as well as the changes induced by the project, varied between teams. Changes were observed for individual team members, for the team as a whole and for the children and their parents. However, changes for individual team members occurred relatively quickly, in comparison with the other changes. To achieve an optimal interdisciplinary team approach all changes are necessary. Therefore, we postulated four hierarchical steps in the development of an interdisciplinary team approach: (1) process-oriented approach, (2) result-oriented approach, (3) problem-oriented approach, and (4) interdisciplinary team approach. Conclusion: It took a considerable amount of time to achieve the interdisciplinary team approach by implementing the Children's RAP. However, the first steps are not only rewarding in themselves, but also prerequisites for further improvement.