Abstract-Alkaline gel electrophoresis of isolated cells (comet assay) was used to assess degree of nuclear DNA damage in populations of terrestrial mollusks Bradybaenafruticum Müll., Chondrula tridens Müll., Cepaea vindobonensis Fer., and Stenomphalia ravergieri Fer. living in the forest-steppe landscape of the southern part of the Mid-Russian Upland. Evidence of differences in the parameters studied was found. The age dynamics of the degree of damage of the genetic apparatus was observed. Possible causes of the identified differences are discussed.