Serology is currently the method of choice for the laboratory diagnosis of Lyme borreliosis, but it must be interpreted with caution. A total of 954 patients with suspected Lyme borreliosis were evaluated on the basis of clinical and serological data. The seroprevalence of Borrelia burgdorferi antibodies was 4.4% (42 of the 954 serum samples). The most frequent clinical manifestation was erythema migrans which occurred in 50% of the seropositive patients, followed by neuroborreliosis (16.6%) and arthritis (11.9%). Carditis was rare. Our findings suggest that for the diagnosis of Lyme borreliosis, serologic tests need to be combined with clinical signs and symptoms. Copyright © by BIOLIFE, s.a.s