Objective of the study is to detect circulation of plague agent and agents of other zoonotic infections (tularemia, pseudotuberculosis, leptospirosis, West Nile fever, Lassa fever, Dengue fever, Chikungunya fever, CrimeanCongo hemorrhagic fever, Q fever, Hantaviruses, tick-borne encephalitis, human monocytic ehrlichiosis, granulocytic anaplasmosis, and borreliosis) among small mammals and their ectoparasites in the territory of seven northern provinces of the Socialist Republic of Vietnam. Materials and methods. We have carried out epizootiological survey of seven northern provinces of the Socialist Republic of Vietnam (Dien Bien, Lai Chau, Lào Cai, Hà Giang, Lạng Sơn, Cao Bằng, and Quảng Ninh). Over the period of the study, 3400 trap/nights were accumulated, 179 specimens of small mammals caught, belonging to 10 species, 213 fleas of seven different species – collected, and 143 specimens of gamaside ticks falling under two species. The material gathered was investigated using enzyme immunoassay and polymerase chain reaction at the premises of mobile laboratory for monitoring and diagnostics. Results and discussion. Two-fold testing of 136 blood samples from small mammals revealed antibodies to F1 of Y. pestis in 14 (10.3 %) of them. Investigation of 158 samples of lung and kidney suspensions of small mammals showed that 22 (13.9 %) samples contained 16S rRNA of pathogenic leptospira, Leptospira spp. Analysis of 60 brain samples for the presence of Leptospira spp. revealed three (5.0 %) positive ones. 25 samples of gamaside ticks were tested for the presence of the DNA of Q fever, plague, tularemia and granulocytic anaplasmosis agents, and for the RNA of tick-borne encephalitis, human monocytic ehrlichiosis, and borreliosis agents. One sample (4 %) of gamaside ticks, Laelaps echidninus, contained RNA of Borrelia.