Ticks are recently regarded as ones of the most important vectors of emerging diseases. One of these diseases is human granulocytic ehrlichiosis caused by obligatory intracellular microorganism recently named as Anaplasma phagocytophilum. 334 sera from forestry workers and 56 sera from blood donors (as a control group) were collected and examined for antibodies to A. phagocytophilum and B. burgdorferi. The antibodies were found statistically more frequently in sera from foresters compared to sera of the control group, both to A. phagocytophilum (19.8% vs. 5.4%, p< 0.001) and B. burgdorferi (32.0% vs. 7.1%, p< 0.01). Only 15 sera (4.5%) were found positive for both examined bacteria suggesting inhibition of coexistence although it was not statistically significant. No correlation was found between percentages of antibodies to A. phagocytophilum and to B. burgdorferi from different locations.