The European Neuroblastoma Group of the International Society for Paediatric Oncology (SIOPEN) is dedicated to the research and treatment of neuroblastoma. The medical research network SIOPEN-R-NET is an extensive web-based European IT network for interdisciplinary biomedical research. The IT infrastructure has been built using state-of-the-art multi-tiered architecture principles. Basic features required for electronic data capture in clinical trials were implemented. Additionally, advanced tools were developed for registration, review, user management, communication and image management. Currently three clinical trials and eight supporting scientific studies are implemented. The medical research network is already in use by 345 active users from 240 institutions in 18 countries. More than 960 000 item entries and 7962 images from 1260 patients are stored. Challenges, which resulted from the fact that only 16 % of the centres had more than 2 patients per year, have been addressed by an intuitive user interface, hierarchical roles, user required features, and experienced support. The system has already been used extensively and has helped to make significant progress in the area of Neuroblastoma research.