Molecular methods were used to study variation in the taxonomic structure of bacterial, archaeal, and fungal communities in soil samples taken along a salinity gradient from a solonchak in the vicinity of Lake Akkol' (Shingirlau, Kazakhstan). Soils from arable fields located 195 km from the solonchak served as the control. Total DNA was isolated from every sample and analyzed by T RFLP and real time PCR. Saliniza tion was found to be the main ecological factor determining the structure of soil microbial community in the study region. The values of Simpson's index characterizing the diversity of this community proved to be sim ilar in all the samples, which, however, significantly differed in the taxonomic composition of microorgan isms. A significantly increased content of archaea was revealed in the sample with the highest salinity. The results of this study show that the structure of soil microbial community reflects specific features of a given soil and can be used as an indicator of its ecological state.