Bartonella henselae and Bartonella quintana infections result in illnesses with symptoms of severity ranging from mild lymphadenopathy (CSD) to systemic disease. The aim of the study was to estimate a prevalence of B. henselae and B. quintana infections in human in Poland. Serum samples collected from 265 patients in 1998-2001 were tested for the presence of antibodies specific to B. henselae and B. quintana. Levels of serum IgM and IgG antibodies to Bartonella henselae and Bartonella quintana were measured with indirect microimmunofluorescence test (MRL Diagnostic, USA). Cats' sera were assessed with indirect microimmunofluorescence test (MRL Diagnostic, USA) and goat immune serum anti-cat IgG FITC conjugate (Sigma, USA). Bartonella henselae specific antibodies were detected in 146 (57.0%) patients with lymphadenopathy. From that number 11.3% have shown specific Bartonella henselae IgM serum antibodies. Bartonella quintana infection was detected with serological methods in 4 patients. It has been found that CSD is a seasonal infection, with most cases occurring in autumn. Most cases of the disease have been recognized in children 8-16 years old. Most of CSD cases (30.1%) were detected in Mazowieckie voivodeship. There were no cases of CSD in Pomorskie, Podkarpackie, Lubuskie and Opolskie voivodeship. The seroprevalence of Bartonella sp. infections in cats was estimated on 86% (31/36). The highest titer of specific Bartonella henselae antibodies detected in cats was 1024. The number of detected Bartonella henselae infections in Poland is very low. It is very probable that the number of cases is underestimated in our country. Cat scratch disease is the most frequently clinically and serologically identified bartonellosis.