Abstract: The article presents the results of studies analyzing the population dynamics of Microtus ilaeus in the lower Amudarya. It has been established that in the conditions of the South Aral Sea region, the moisture content of the territory for the vole population is a limiting factor in the autumn period. This confirms that under pessimum conditions, the vole population is very sparse and its abundance is limited mainly by external factors. The effect of all analyzed factors on the dynamics of the vole abundance is always complex, interdependent and variable depending on the population density and the totality of the conditions of its existence.