The study aimed to evaluate late clinical symptoms and serological changes in persons with erythema migrans (EM) diagnosed 4-11 years ago who were not treated with antibiotics. Among initially included into the study 28 untreated EM cases, twelve persons responded for invitation to the Department. The symptoms and signs which could be related to previous Borrelia burgdorferi infection were present in 9 (75%) untreated patients. They included ischialgia (42%), arthritis (33%) and positive serological tests results (33% of patients, including 2 with clinical signs). These results demonstrate that lack of antibiotic treatment in the early LB stage can result in the development of late disease manifestations.