Orphanet is the European portal dedicated to information on rare diseases and orphan drugs for patients and their families, health professionals and researchers, support groups and industry. Its aim is to contribute to the improvement of the diagnosis, care and treatment of patients with rare diseases. Orphanet provides an encyclopaedia of rare diseases, a directory of services in Europe including specialised clinics, clinical laboratories, research projects, registries, clinical trials and support groups concerning rare diseases and publishes an on-line newsletter. Orphanet is run by a consortium of European partners. It is managed by INSERM and funded by INSERM, the French Ministry of Health and the European Commission (DG Public Health).