Borrelia (B.) burgdorferi, the causative agent of Lyme disease, is the most important zoonotic pathogen in the northern hemisphere. This report describes a peregrine falcon (Falco peregrinus) infected with B. burgdorferi. The patient was presented with a swollen intertarsal joint, diarrhoea, and a reduced general condition. Radiographs were inconspicuous. Antibacterial treatment against the bacterium Escherichia coli found in the intestine and joint did not lead to success. The serological testing for B. burgdorferi was positive. The bird recovered well after a therapy for borreliosis similar to that in humans and mammals. In future, it should be taken into account that raptors are susceptible to B. burgdorferi.