Finding out information about rare chromosomal aberrations can be difficult both for patients and doctors. It is a vast subject area and geneticists are now working with new techniques for detecting abnormalities which means that the number of identified abnormalities will rise. The ECARUCA website was founded as a way of clarifying and organising information about the subject. ECARUCA allows everyone who has an interest in chromosomal abnormalities to access current information about the subject and connect with others including patients, their families and professionals. The ECARUCA website has both public and private pages that users can access. Public pages, which can be accessed by the general public, give details about the project's objectives and general downloadable information about chromosomal disorders. The private pages, which can only be accessed with password protection by registered account holders contain patients' personal data, lists of participating centres, a case of the month study and a search facility by chromosomal aberration. There are also restricted pages for children's cases that can be accessed by their parents who can then send follow up information to the database managers. Information updates are disseminated regularly by means of a newsletter. ECARUCA is currently being visited by more than 300 people per week. Over 500 professionals in the field of clinical cytogenetics have accounts and access the site regularly. The website is proving successful for connecting patients with chromosomal disorders, their families, doctors, scientists and all others involved in the area of chromosomal aberrations. It is hoped that ECARUCA will become an international forum for clinical cytogenetics.