The dynamics of the number and genetic structure of populations is one of the leading factors determining the success of the existence of populations in time and space. Based on observations (changes in numbers) and molecular genetic analysis data (CR and cyt b), the dynamics of the demographic and genetic structure of the populations of russet (Spermophilus major Pall.) and speckled (S. suslicus Güld.) ground squirrels in the sympatry zone were studied.