Lyme borreliosis is an emerging zoonosis transmitted by infected hard-bodied ticks. The disease is multisystemic. In the initial stage its typical manifestation is the erythema migrans, a cutaneous lesion that occurs in up to 90% of patients. In order to investigate the presence of the specific agent, Borrelia burgdorferi, in the early stages of the disease, DNA from skin biopsies, urine and peripheral blood of 30 patients with clinically documented erythema migrans and without apparent systemic involvement was analysed by polymerase chain reaction. Borrelia DNA in both blood and skin biopsies was detected in 23 patients, while in 9 patients it was discovered in urine and skin biopsies. These results demonstrate that Borrelia DNA is detectable systemically also in patients with early Lyme borreliosis and strongly suggest a possible dissemination of the causative agents even when only a local infection is assumed.