Lyme borreliosis (LB) is a zoonotic disease, caused by spirohete Borrelia burgdorferi sensu lato (Bb-sl). It is transmitted through the bite of infected tick (Ixodes ricinus), which feeds on animals. In Slovenia, LB is endemic. LB in dogs is clinically difficult to identify, as it is not typical, and may appear as anorexia and fever. The infection in dogs is most often determined by the evidence of specific antibodies. In the master's thesis, two methods were compared: the immunofluorescence test (IFT) and the immunoblot (IB) with which we proved specific IgG antibodies. In the study we included 100 dog blood samples suspected of LB. The purpose was to demonstrate the presence of anti-Lyme borreliosis antibodies using both methods, compare results, and determine the response of the borrelia antigens in dogs. We have found, that with IB was 22 % of samples positive and 1 % borderline, in the meantime in the IFT 36 % was sera negative. Statistically significant difference between both tests were shown at IFT titer 64, where with IFT 12 samples were positive, while with IB 11 samples were negative and one positive. A smaller significant difference among results appeared at titer 128, where with IFT nine samples were positive, while with IB seven samples were negative and two positive. At the highest titres (256 in 512), the results were evaluated equally, with titers lower than 64 differences between tests were not statistically significant. At IB, the most commonly found was the reaction to antigen VlsE.