The National Neurofibromatosis Foundation International Database is a system for collecting comprehensive information on the clinical manifestations and natural history of neurofibromatosis. Data are entered into personal computers at participating centres and are pooled at the Central Database and coordinating centre in Vancouver, Canada. The system includes special mechanisms to assure consistency among centres and to maintain patient confidentiality. The database is designed to foster collaborative clinical and molecular genetic research in many aspects of neurofibromatosis.