Lyme borreliosis represents the most important tick-borne zoonosis in Europe. In dogs anorexia, fever, alternating lameness and arthritis indicate most strongly the presence of the disease. The typical erythema chronicum migrans in human cases is seldom seen in dogs. Seroconversion in dogs becomes relevant for diagnosis of Lyme borreliosis only in connection with previous or present clinical symptoms. A canine Borrelia burgdorferi antibody test kit (Cite Lyme Test) proved 95 Prozent conformity with the IFAT and ELISA. In cases of negative sera the agreement was 100 Prozent. When positive reaction in the test kit is seen, it is advisable to check two further serum samples in 4 weeks intervals with IFAT in order to observe the dynamics of the titers.