After the isolation of Borrelia burgdorferi, the previously unknown causative agent of Lyme disease, two neurological disorders, Bannwarth's syndrome and acrodermatitis chronica atrophicans-associated neuropathy, which have been known in Europe for decades, gained new interest. With the availability of serodiagnostic tests, a chronic debilitating disorder--progressive borrelia encephalomyelitis--was found to be caused by chronic infection with B. burgdorferi. Beside these typical manifestations, a growing number of publications about various neurological phenomena appeared, which were thought to be caused by B. burgdorferi. This assumption was based in many cases on the results of serodiagnostic tests only. Considerations for causal connections were frequently lacking. While prior to the availability of serodiagnostic tests neurological manifestations of Lyme borreliosis frequently remained undiagnosed, we now face a tendency for overdiagnosis. The great variety of neurological manifestations in Lyme borreliosis--most of them can also be attributed to other conditions--and the high rate of seropositivity for B. burgdorferi amongst the population living in endemic areas require strict criteria for the correct diagnosis of new and typical neurological manifestations.