The collection, processing, validation, verification, formatting, filing, and storage of the required input data are some of the most important components in the National Institute for Occupational Safety and Health (NIOSH) Radiation Dose Reconstruction Program. Without question, the quality and scientific validity of the reconstructed dose estimates are totally dependent on these aspects of the program. Of equal importance is that the data be filed not only in a readily accessible format, but also in one that facilitates error-free retrievability. One often unrecognized key factor is that each and every item of data must be collected with careful consideration of the use to which it is to be applied. Two important databases have been established in support of the dose reconstruction operations. They are the NIOSH Office of Compensation Analysis and Support Claims Tracking System and the Site Research Database. The former contains information directly relating to individual workers. When such information is not available, surrogate sources (i.e., area monitoring data) are used to establish the "radiation environment" in which the worker was employed. This information is uploaded into the Site Research Database. Procedures for these systems entail identifying, collecting, and processing information from more than 300 Department of Energy and Atomic Weapons Employer related facilities. To date, more than one million worker-related employment and dosimetry records and more than 33,000 research documents have been uploaded into the associated computer systems.