Rare diseases include a group of conditions characterized by a prevalence lower than 5 per 10,000 in the community. In France, any rare disease affects less than 30,000 patients and often much less. Three to 4% of children and 6% of the population in Europe are affected. It is a true public health stake since most diseases do not have any curative treatment. In France, the Ministry of Health has initiated a National Rare Diseases Plan. Twenty five out of 132 labelled Reference Centres (RC) decided to share a common Information System named CEMARA. It is dedicated to collect continuous and complete records of all patients presenting with a rare disease, and their follow-up. The main objective of CEMARA is to contribute to the missions of the RC regarding the registration and description of their activities, coordination of the network of their correspondents, organization of the follow-up of rare diseases, and analysis of the epidemiological patterns. A description of CEMARA is provided as well as its cooperation with Orphanet and Genatlas, and a presentation of 11803 current records collected by more than 300 health care professionals belonging to more than 70 sites.