The characteristic of medical and dosimetric register database of Siberian Group of Chemical Enterprises personnel is represented. This characteristic includes the description of the database structure, main sources of information, quantitative composition of the cohort under study, methods of evaluation of the external and internal irradiation doses, modern data on cancer incidence and reasons of death. The database is the basis for estimating the risk of the cancer and non-cancer effects after a long-term radiation exposure and dependence of "dose-response" at different levels: from population and group to cell and molecular. Now the database of register contains the information about more than 66,500 employees at the Siberian Group of Chemical Enterprises, about 22,000 of whom were exposed to external irradiation and more than 7500 employees--to internal irradiation. The register is the information resource of a large biological material bank. Using this bank, the research of chronic radiation exposure genetic effects and markers of individual radio sensitivity is performed.