Yhe aim of the study was the investigation of the dynamics of LB prevalence in central Europe over a 12-year period and estimation of its dependence on the environmental factors and on the level of medical services. Epidemiological studies of LB were conducted in the years 1996-2007 in 9 regions of the Świętokrzyskie province in south-eastern Poland (Central Europe). On the basis of patient registry, the incidence, prevalence in various months of the year, the mean number of cases in various seasons and the seasonality factors (SF) of LB were calculated. Between 2000-2007, an increased borreliosis incidence was observed in the study area. During the entire study period, the highest incidence (25.93 and 30.66) was observed in the regions with the highest density of Ixodes ricinus ticks - vectors of Borrelia burgdorferi spirochetes, and where the inhabitants are offered the best available LB diagnosis and treatment due to a sufficient number of doctors (r = 0.74) and all medical personnel (doctors, nurses and diagnosticians) (r = 0.89). The highest LB incidence was present in the summer and autumn seasons (SF = 113.25 and 155.18%) in the areas with the highest density of nymphs and adult I. ricinus ticks (> =19/1 h of sampling). Improved standards of public medical care as well as environmental monitoring of tick threat may contribute to a decrease in prevalence of LB and to its better detection.