In the last few year s there has been observed an increased incidence of Lyme borreliosis (LB) in Estonia. When in 2005 there were 20.9 cases per 100 000 inhabitants then in 2008 there were already 106.0 cases per 100 000 inhabitants. The issue is whether this is a reality, or whether overdiagnosing could sometimes be involved. In endemic regions, a careful clinical evaluation of patients for the diagnosis of LB is of particular importance, and epidemiological, clinical, and serological data have to be considered jointly. Since the symptoms are often unspecific, other diseases (rheumatologic, neurologic, or thopedic, etc.) should be considered and searched for in case additional examinations are performed.