Between 2009-2010, a group of 259 patients suspected of contracting Lyme disease were examined in the Provincial Sanitary-Epidemiological Station in Olsztyn for the presence of IgM and IgG against specific Borrelia burgdorferi sensu lato (s.l.) genospecies antigens by immunoblot. A total of 27.4% and 29.0% of the blood serum samples showed positive and uncertain results for IgM and IgG antibodies. The majority of positive and uncertain results were found in patients aged 30-40 years (30%) for IgM, and people aged 50 and over (35.8%) for IgG. Significantly more positive results for IgG were found in males (40.2%) then females (19.7%). In both groups, similar proportions of positive results for IgM anti-Borrelia were recorded (26.1% of females and 29% of males. In 71.5% of patients, IgM against flagellin protein (p41) of B. burgdorferi sensu stricto (s.s.) was found. For IgG, the most frequently detected antibodies were found against the p41 protein of B. burgdorferi s.s. (64.8%) and the recombinant variable surface antigens (VlsE) (49%). Among all the analysed antigens those of B. burgdorferi s.s. were the most frequent cause of immunological reaction, followed by antigens of B. afzelii and B. garinii. Reaction to antigens of B. spielmanii was rarely detected.