The investigation deals with the enzyme immunodiagnosis of trichinosis in some mammalian species involved in the circulation of this widespread menacing anthropozoonosis in the natural synanthropic foci in the Russian Federation. The use of T. spiralis immunodominant antigens of a molecular mass of 63-29 kDa as enzyme immunoassay (EIA) diagnostic kits for the lifetime diagnosis may ensure a rather effective lifetime detected of the Trichinella-infested omnivores and carnivores (pigs and cats) participating in the circulation of the causative agent in the synanthropic foci. Also, these antigens are suitable for the study of the immunological aspects of tricinosis when T. spiralis invasion is simulated on laboratory animals (rodents). False-negative EIAs are associated with the specific features of immunological responsiveness of each organism, the degree of infectivity (immunological tolerance in intensive inoculation), the stage of invasion, the biological characteristics of a helminth (such as the immunosuppressive effect of the parasite on the host during larval migration), rather than with the quality of the used components of a response.