UNLABELLED: The goal of this work was to provide comparative genetic characterization of the human and animal Brucella melitensis isolates from Mongolia, Russia and Azerbaijan using current molecular-genetic typing methods. MATERIALS AND METHODS: Twenty eight Mongolian (n = 18), Russian (n = 6), and Azerbaijan (n = 4) human and animal Brucella melitensis isolates were studied using 2 molecular typing methods based on PCR for differential species and biovar specific ORF (open reading frames) molecular targets and MLVA (multiple locus variable number tandem repeats analysis) using primers to 12 known loci. RESULTS: The PCR was used for differential molecular targets (all B. melitensis isolates) were characterized as the B. melitensis biovar 2. The MLVA revealed 7 identical and 5 variable MLVA loci. All the isolates were classified into 25 genotypes using the dendrogram on the data of 12 loci and the cluster related to reference strain B. melitensis 63/9 biovar 2. The B. melitensis isolates having related MLVA genotypes were connected to Mongolian, Russian and Azerbaijan regions. The circulation for two B. melitensis isolates to not typical hosts as camel and yak was demonstrated using molecular typing methods. CONCLUSION: The genetic characterization of twenty eight B. melitensis isolates from different geographical regions in Mongolia, Russia, and Azerbaijan recognized genetic relationships. On the other hand, the MLVA has high discrimination power with a resulting Hunter and Gaston discriminatory index (HGDI) of 0.9841 revealing genetic diversity for the isolates forming of 25 MLVA genotypes. To improve the system of the brucellosis surveillance in Russia MLVA typing of B. melitensis isolates are necessary to investigate from the Siberian (Republics Tuva, Buryatia, and Irkutsk region) and South (Republics Dagestan, Kalmykia, and Stavropol region) Districts having frontier areas with Mongolia and Azerbaijan.