Based on the information provided in the 2nd and 3rd editions of the Red Book of Mongolia, the current state of the rare and endangered species of mollusks, crustaceans and insects of Mongolia and the threat to their existence are analyzed: water pollution and accidental catch during fishing (for aquatic species); degradation of habitats (haying, draining of swamps); overgrazing; collecting. The effectiveness of protection measures has been identified: the habitats of some species are included in the boundaries of specially protected natural territories; some species are listed in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora which will establish strict control over the international trade of rare and endangered species of invertebrates in Mongolia. It is indicated that the conservation of certain species of mollusks, crustaceans and insects requires additional and more specific measures: prevention of habitat degradation, including overgrazing and pollution of water bodies; a ban on collecting; conducting research to identify the concentration of populations, as well as assess the resources of food plants.