The results of research conducted in the period 2002–2004 and 2019–2022 on the study of the ecology of gamasid mites living on biocenoses of cotton, wheat and melons in the northern regions of Turkmenistan are presented. In particular, 10 species of gamasid mites were identified in the listed biocenoses, including 3 new species for the fauna of the country. According to the selectivity of ecological niches, the discovered mites are classified as eurybionts and geophyllobionts. The importance of predatory gamasid mites in biocenoses is shown in regulating the number of herbivorous mites. Some insects and nematodes, the role of gamasid mites as the main component in the biocenosis, which ensures the functioning of the predator-prey relationship, is proved. Laboratory observations revealed the specificity of the choice of prey by predatory mites in the species B. tarsalis, Ph. plumifer and N. bicaudus. The specifics of the choice of prey by the tick Ph. plumifer in the laboratory in the optimum temperature range of +20 – +25°C and a humidity degree of 40-65%. They actively bred on tea rose leaves when C. pulcher was used as a mite victim. The results of observations under a stereomicroscope on the study of the ethological characteristics of the predatory mite N. bicaudus during its attack on its prey in the leaves of an apple tree are also presented. Researches have revealed the specificity of the choice of the herbivorous mite Siteroptes tameri by the predatory mite N. bicaudus as a prey. The active role of the latter in the spread of spores of the fungus N. gossypii has also been proven. Field observations revealed that predatory mites G. aculeifer, B. tarsalis and N. bicaudus feed on herbivorous mites in biocenoses. For predators, specific types of prey have been established, related to spider mites, acaroid and eriophyid mites. The role of gamasid mites in establishing the ecological balance of herbivorous mites in biocenoses has been proved.