Over the past 3 years, the number of new cases of brucellosis has increased in the Russian Federation. Brucellosis remains an important problem in regions with developed livestock farming; however, cases of diseases in animals and humans can also be recorded in other regions. The article describes an outbreak of brucellosis in a peasant farm affecting 148 heads of cattle and 4 farm employees in the Novosheshminsky municipal district of the Republic of Tatarstan. The disease was caused by Brucella abortus. Epizootic and epidemiological maps of the outbreak, sanitary and epidemiological survey activities, and sanitary and hygienic characteristics of the working conditions were analyzed. Data from the case histories of four peasant farm workers with brucellosis are also presented. The most likely cause of the epizootic was the unauthorized import of cattle, and infections in humans were caused by noncompliance with working conditions and personal-protective measures by farm workers. Brucellosis cases are more often recorded in endemic areas. However, with poor veterinary and sanitary control in any territory, epizootics are possible, which pose a danger in terms of damage to the national economy and possible infection in humans, primarily the professional risk groups. The disease does not have pathognomonic symptoms and can be suspected only if doctors are aware of them, evaluate the results of preliminary and periodic medical examinations with laboratory examinations of “at-risk” populations, and subject them to a thorough collection of epidemiological history.