439 sera of patients from eastern Slovakia suspected of Lyme borreliosis were examined for anti-Borrelia IgG and IgM antibodies by ELISA (Ezygnost, Dade Behring, Germany). Out of the total number of 64 sera, e.g. in 14.6% found anti-Borrelia antibodies were. Among seropositive patients, 54.7% were women and 45.3% men. The highest incidence of the disease was diagnosed in the group of women aged 55-64 and men aged 45-54. Out of 29 positive sera of men, 55.2% had IgG antibodies, 27.6% IgM antibodies and 17.2% both types of antibodies. Out of 35 positive sera of women, 48.6% had IgG antibodies, 40.0% IgM antibodies and 11.4% both types of antibodies. Erythema Chronicum Migrans--ECM (31.3%) and arthritis (25.0%) prevailed among clinical symptoms, in contrast with only 7.8% of neurological cases. In men, arthritis most frequently occurred (27.6%), while in women erythema migrans forms (37.1%). Other manifestations of the disease appeared in 13 patients (20.3%), and 10 patients (15.6%) had no record of clinical manifestations. As shown by patients' records, 32.8% reported attachment of tick, 20.3% insect bites and 29.7% were not aware of being bitten by vectors. Seasonal dynamics of diagnosed cases reached three peaks with the highest numbers in February, May and October.