Some results of investigations of geno-demographical structure variability of populations and their biological indexes under the influence of external conditions, turned out at the territory of the republic of Belarus, are summed up in this article. The radiation factor as a result of Chernobyl's Power Station accident is added to a lot of other anthropogenic effects such as industrial waste and pesticides. Also considerable aggravation of social-economic conditions of the most of people of the republic has taken place in last few years.
