The National Disease Research Interchange (NDRI) develops and maintains sources of viable human tissues and organs for use by the general biological and biomedical research community. Tissues are retrieved, preserved and delivered to research investigators at their request. The NDRI serves investigators at research institutions throughout the nation. The NDRI is actively involved in the use of human cells and tissues as model systems in a wide range of biomedical research endeavors. Applications seeking to use NDRI's services are reviewed for relative scientific merit by an external board of scientific advisors. The requests from investigators having NIHfunded research projects will normally receive priority when demand for a tissue exceeds its supply.