The objective of the present study was to assess the risk of borreliosis and anaplasmosis (ehrlichiosis) among the forestry workers of the Roztocze National Park (south-eastern Poland) by examination of Ixodes ricinus ticks living in park area with PCR method, and by the serological and clinical examination of the workers. In 406 examined ticks, the prevalence of infection with Borrelia burgdorferi sensu lato was 11.5 %. The nested PCR reaction for determining the genospecies showed that the most common was Borrelia burgdorferi sensu stricto (55.3 % of total positive) followed by Borrelia afzelii (38.3 %). As many as 6.1 % out of 115 examined ticks showed the presence of Anaplasma phagocytophilum DNA. The infection rate was high in males and females (14.3 % and 11.1 % respectively) and low in nymphs (1.5 %). In 46 out 113 examined forestry workers (40.7 %) the presence of specific IgG and/or IgM antibodies against Borrelia burgdorferi sensu lato was found in ELISA test, while only 4 out of 56 urban blood donors showed a positive response (p<0.0001). The prevalence of IgG antibodies against Anaplasma phagocytophilum determined with the use of indirect immunofluorescence test (IFA) was 17.7 % in forestry workers compared to 5.4 % in reference group of blood donors (p<0.05). No correlation was found between the presence of antibodies to A. phagocytophilum and to B. burgdorferi s. l. Clinical investigations of 113 forestry workers showed 3 cases of borreliosis (2.7 %) and no cases of anaplasmosis (ehrlichiosis). In conclusion, forestry workers of the Roztocze National Park in south-eastern Poland are often exposed to Ixodes ricinus ticks infected with Borrelia burgdorferi and Anaplasma phagocytophilum, and show a high proportion of asymptomatic borreliosis and anaplasmosis (ehrlichiosis) manifested by a positive serologic response, while the number of clinical cases is relatively low.