We conducted the first seroepidemiological study to evaluate the exposure of zoo animals to Borrelia burgdorferi s.l. in German zoos and wildlife parks. A total of 1487 individuals representing 148 ungulate and carnivore species belonging to 19 families were examined using a non-species dependent ELISA. Specific antibodies were detected in 154 (10·4%) animals; 168 (11·3%) sera produced borderline results. The percentage of seropositive individuals was related to species and origin (zoo), and increased with age of the animals. Sex and season did not influence seroprevalence. Examination of 600 ticks (Ixodes ricinus; caught from vegetation in the zoos) by darkfield microscopy and indirect immunofluorescence technique revealed infection rates within the range typical for Central Europe. The results substantiate that there is an infection risk for zoo animals. A differential diagnosis of Lyme borreliosis should be taken into account in case of suspicious clinical symptoms and possible contact to ticks.