Data which prove the important role of the lipid (as well as chromatin-bound lipids) peroxidation free radical reactions in the mechanisms of nuclear genome components damages are presented. Free radical nature of chromatin damages is proved in case of effects of ionising radiation and heavy metals ions. The role of lipid peroxidation reactions in the effects of the natural aging process, chlor- and phosphororganic chemicals intoxications is less investigated. The importance of the research of this scientific problem is discussed because of the unfavorable chemical and radiation situations.