Wild canids can play an important role in the transmission and maintenance of metazoan parasites in natural foci [3, 8]. However, little is known about the blood parasites of foxes and other wild living carnivores. In our study, we focused on Anaplasma phagocytophilum infection of red foxes (Vulpes vulpes) in the north-eastern part of Poland. The main vector of A. phagocytophilum in Poland is Ixodes ricinus tick [1, 13], and the animal reservoirs are small rodents and ruminants [2, 4, 5]. However, other mammals able to serve as animal reservoir are still being found.