FIELD: biotechnology. SUBSTANCE: the present innovation deals with animal gene engineering and could be applied in veterinary microbiology to detect agent of necrobacteriosis in ruminants - Fusobacterium necrophorum and differentiate it against atypical forms of Fusobacterium pseudonecrophorum and other microflora. The method includes synthesis of external - 
and internal - 
oligonucleotide primers, synthesis of complementary DNA upon chromosomal DNA matrix followed by synthesis of, firstly, external and, secondly, internal fragments. Amplification of synthesized DNA should be carried out due to polymerase chain reaction (PCR) to analyze the size of PCR products. The suggested method is of high specificity and sensitivity and enables to differentiate Fusobacterium necrophorum obtained out of lesion foci against atypical forms and accompanying microflora. EFFECT: higher efficiency of detection. 1 ex, 1 tbl
