National Death Index
The National Death Index (NDI) is a central computerized index of death record information on file in the state vital statistics offices. Working with these offices, the National Center for Health Statistics (NCHS) established the NDI as a resource to aid epidemiologists and other health and medical investigators with their mortality ascertainment activities. The NDI is a national file of identifying death record information (beginning with 1979 deaths) compiled from computer files submitted by state vital statistics offices. Death records are added to the NDI file annually. The NDI can be used by investigators to determine whether persons in their studies have died and, if so, to obtain copies of the matching death records from state vital statistics offices. NDI matches are available to investigators solely for statistical purposes in medical and health research. The system is not accessible to organizations or the general public for legal, administrative, or genealogy purposes.
http://www.cdc.gov/nchs/ndi.htm and related web pages.