A symposium called "Contribution of modelling in the paediatric drug development" was organized at Paris on July 5-6, 2007 under the auspices of INSERM. The following issues were highlighted and discussed by the participants at the end of the meeting during a round table: *What is the place of modelling at a preclinical stage in the paediatric development? *What is the place of modelling at a clinical stage in the paediatric development? *What are the requirements for an evaluation based on modelling? *What are the recommendations and guidelines need to be established to facilitate the use of modelling techniques in paediatrics? This paper summarizes the discussion around these four questions.