Many bacterial and/or viral infections can affect several organs and apparatuses. Some of these infectious agents may be implicated in the pathogenesis and evolution of chronic connective and articular diseases. Such agents may trigger the start of articular chronic diseases or may play a role in maintaining the symptoms. In this study, we evaluated the sensitivity and specificity of polymerase chain reaction (PCR) in Lyme borreliosis, in patients with a confirmed diagnosis of the disease after clinical examination and standard serologic tests. There were 18 true positive results from nine samples from patients with present clinical signs, positive PCR, negative Western blot and/or enzyme-linked immunosorbent assay (ELISA) and nine samples with present clinical signs and positive ELISA and/or Western blot. The 51 true negative results were negative in all three methods used. There were 24 false positive results, positive for clinical signs, ELISA and/or Western blot but negative for PCR.