Relevance. The reproductive health of dairy cows is one of the top priorities in dairy farming. Viral diarrhea, a disease of mucous membranes in cattle, is one of the causes of impaired reproductive function on farms. The disease is widespread throughout the world and causes significant economic damage, which consists of a decrease in productivity, lack of offspring, impaired reproductive function of the broodstock, costs of treatment and specific prevention. The viral diarrhea virus has an immunosuppressive effect. Diagnosis is complicated by a “blurry” clinical picture due to the association of the virus with other respiratory-intestinal viruses and the addition of a secondary bacterial infection, as well as the presence of a persistent form of infection. The diagnosis requires the analysis of clinical and epizootic data, pathological changes and a combination of several methods of laboratory diagnostics. An important link in the prevention and recovery of herds is the conduct of epizootic monitoring and analysis of its results.Methodology. The assessment of the epizootic situation for viral diarrhea, a disease of mucous membranes in cattle in the Russian Federation for 2020, was carried out based on the results of the analysis of information obtained from annual reports provided by state veterinary laboratories in the FSBI CNMVL in the form of 4-vet (annual).Results. Based on the results of the epizootic monitoring, it can be concluded that the viral diarrhea virus is widely circulating in the livestock farms of the Russian Federation. In 2020, positive results were recorded in all federal districts of the Russian Federation (in 33 subjects), except for the Far Eastern Federal District. The most difficult epizootic situation is in the North Caucasus Federal District and the Central Federal District (38% and 29% of the total number of positive results, respectively).