Radioactive contamination of the environment in Siberia (Russia) begun in 1949 when was accomplished the first explosion of a nuclear device at the Semipalatinsk Test Site (Kazakhstan). It is known that the explosions of nuclear devices in the atmosphere were accomplished regularly until 1963. Radioactive fallout from the explosions had contaminated several densely populated areas of Siberia, mainly the Altai region. Since then, more than 3,000,000 inhabitants of Siberia and the Urals has been exposed to radiation due to testing of nuclear devices at the Semipalatinsk and Novaya Zemlya Test Sites as well as accidents at some sites involved in the manufacture of nuclear weapons such as the Siberian Chemical Complex (Seversk), the Mayak Chemical Complex (Ozersk), and the Mining-Chemical Complex (Zeleznogorsk). In this work, we report the results of genetic and biomedical examinations of the local population inhabiting in the Altai region, the Altai Republic and people living close to the nuclear facilities of Zeleznogorsk, Seversk and Ozersk who were exposed to radiation, as well as the participants of eliminating the consequences of the Chernobyl accident.