Lyme borreliosis (LB) is a tick-borne spirochetosis caused by Borrelia burgdorfei (Bb) and transmitted by the bite of infected hard-bodies ticks of the genus Ixodes. LB is a multisystemic disease involving skin, joints, nervous system, but also heart and eyes could be involved. The diagnosis of LB is primarily based on clinical and epidemiological criteria, but also serological tests, histological evaluation and cultivation can provide useful supporting evidence. Late involvement of skin, nervous system, joints can also arise after a long period from the thick bite, even after its apparent eradication. In this review we describe different clinical syndromes related to Lyme disease. The hypothesis on the pathogenesis, the similarities with other diseases, the clinical and diagnostic fundamentals for the differential diagnosis and the proposed treatment are presented.