The epidemiological and some clinical features of tick-borne relapsing fever (TBRF) in the Kirovo-Chepetsk District, Kirov Province were studied and the data were statistically processed. The incidence rates of the disease in the region were compared with those of other Russian regions by sex, age, and occupation. The study revealed where and when infection had occurred, the duration of tick's attachment to the patient with TBRF, determined the duration of its incubative period, assessed whether a short-term prognosis of the expected number of patients can be made by the number of tick-bitten persons. The Kirovo-Chepetsk District is an active highly endemic focus of TBRF. Its incidence is tens of times higher that of other natural and focal infections.