The review is devoted to long-term genetic and epigenetic disorders in exposed individuals and their descendants, namely to cytogenetic effects in the Chornobyl NPP accident clean-up workers and their children, DNA methylation as an epigenetic modification of human genome. Data presented in review expand the understanding of risk of the prolonged exposure for the present and future generations, which is one of key problems posed by fundamental radiation genetics and human radiobiology. The Scientific Council meeting of NAMS approved the NRCRM Annual Report. Key words: Chornobyl NPP accident, cytogenetic effects, DNA methylation.