An NCI Working Group on Epidemiology Data Resources is charged with the development of data resources for cancer epidemiology. It also serves as a review group for Master Order Agreement Requests for Proposals originating in the Epidemiology and Biostatistics Program. Dr. Beebe serves as its chairman. It has been active in regard to access to the files of the Social Security Administration and the address files of the Internal Revenue Service, to the development of a database for occupational mortality based on the coding of death certificates by the states, to the exploitation of the file of discharges from hospitals of the Department of Veterans Affairs, to the management of the National Death Index maintained by the National Center for Health Statistics, and to the facilitation of record linkage by computer.