Introduction: Plague is endemic in a number of states around the world. Despite all public health measures taken to eradicate plague, the disease persists and even reappears in some countries. Today, traditional serological methods searching for the capsular antigen of the plague microbe are widely used to monitor the presence of Y. pestis in the environment. Yet, for the causative agent of the plague, the possibility of eliminating plasmids and maintaining of the ability to cause an infectious process by atypical strains is not excluded, which reduces the diagnostic value of preparations based on the detection of species-specific antigens of the plague microbe. Our objective was to develop biotechnology for the production of immunodiagnostic drugs for detection of the plague bacteria (capsular and capsule-free forms). Materials and methods: When performing the work, 27 strains of microorganisms of pathogenicity groups I–IV of different genera and species were used. Results: The development of immunodiagnostic preparations for the detection of Y. pestis in environmental samples is described. The presented experimental preparations allow detection of typical and antigenically modified plague microbe strains with a positive and/or negative expression of fraction 1. To evaluate the effectiveness of the designed diagnosticums, both laboratory and field testing was performed demonstrating positive results in the study of both artificially and naturally contaminated samples. The possibility of using the plague immunomagnetic sorbent providing selective concentration of material with a low pathogen content and purification of samples from possible contamination with extraneous microflora during epizootological examination was also confirmed. Conclusions: We constructed promising diagnostic preparations that help identify Y. pestis strains in the studied objects regardless of the cultivation temperature and plasmid profile.